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#Post#: 591-------------------------------------------------- |
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A bit about Gearboxes |
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By: Lucy Date: January 5, 2012, 1:43 pm |
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If anyone's interested, this is what the inside of a series 3 |
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gearbox looks like. |
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The Mainshaft |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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The skew cut gears are from left to right, 1st, 2nd and 3rd. |
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These gears when in neutral are free to rotate about the |
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mainshaft. |
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3rd/4th syncro unit |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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1st/2nd gears and syncros, the one in the middle is the dog gear |
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that meshes with the reverse idler |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the reverse idler as viewed through the top cover of the main |
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box |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the layshaft |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the bearing at the right hand end sits in a recess in the end of |
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the gearbox next to the transfer box as seen below |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the image is on it's side the top of the box is to the right you |
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can see the reverse idler (top left) the rear mainshaft bearing |
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(in the middle) and the recess the layshaft bearing sits in. |
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the other end of the layshaft sits in a bearing in the bell |
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housing |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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this is on the left, the bit on the right is the primary pinion, |
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this transmits the drive from the clutch to the gearbox, either, |
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for 1st, 2nd and 3rd via the gear you can see to the layshaft or |
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in the case of 4th as a direct drive through to the mainshaft |
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using the dog teeth visible in the top of primary pinion. The |
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plain silver part you can see is what engages with the syncro |
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cone, as below |
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primary pinion |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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in the above photo 4th gear is engaged. |
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how it fits together |
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The photo below shows how the main shaft and layshaft engage |
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with each other, the primary pinion is on the right and the |
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transfer box end of the mainshaft on the left. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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with the 1st/2nd gear selector |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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3rd/4th selector |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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both |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the reverse selector sits next to these two. |
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syncros |
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a closer look at teh 3rd/4th gear syncro unit |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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The selector fork engages with the dark coloured disc in the |
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middle and moves this either forward for 4th gear or back for |
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3rd. |
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This photo shows it in the 'in gear position' the narrow parts |
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in the silver bars you can see are where the gear cluster detent |
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springs engage to hold the gear in neutral, whilst the box is in |
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1st, 2nd, reverse or neutral. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the teath you can see are the dog teeth that engage with the |
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gears. The photo below shows how 4th gear engages |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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the syncro cones are the brass coloured rings you can see |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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these rub against an area of the gear cluster prior to the dog |
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teeth engaging and help to equalise the speed of the gear and |
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the mainshaft. |
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to remove the mainshaft you have to undo this nut in the |
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transfer box |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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to do this you need a special tool which you can buy or make, |
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either way a homebodged one looks a bit like this |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/gearbox%20small/PI… |
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That's the end of todays tour, you may see me in other such |
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epics as inside your transfer box soon! |
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#Post#: 637-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: RMS Date: January 5, 2012, 3:19 pm |
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Quote |
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"If anyone's interested, this is what the inside of a series 3 |
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gearbox looks like." |
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No it doesn't! Mines all dirty and got chipped teeth ;) |
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#Post#: 719-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: rbrtcrowther Date: January 5, 2012, 4:15 pm |
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That's a suffix A by the looks of the reverse idler. Nice to |
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see the teeth on 3rd 4th syncro look the same as mine with the 4 |
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king teeth next to each other....I wonder why they did that? |
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#Post#: 778-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: Albert Ross Date: January 5, 2012, 4:55 pm |
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Just to add, the 3/4 synchro unit does have a front and a back. |
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The back has a machined out flat edge to fit over a split |
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ring... get it wrong and you have difficulty keeping it in 3rd.. |
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ask me how I know and I'll punch you in the bracket. (Never |
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build a box pissed) |
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#Post#: 814-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: PJ Date: January 5, 2012, 5:27 pm |
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Thanks for this Lucy... maybe I'll crack on and rebuild my spare |
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box now! |
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#Post#: 900-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: seriesewan Date: January 6, 2012, 5:37 am |
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Thats explained a lot! still cant find the mystery part that |
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plopped out in my oil though :( |
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#Post#: 911-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: Lucy Date: January 6, 2012, 6:18 am |
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What Mr Ross says is correct and the photo above shows it the |
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wrong way around :-[ |
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#Post#: 922-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: estwdjhn Date: January 6, 2012, 6:57 am |
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[quote]still cant find the mystery part that plopped out in my |
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oil though[/quote] |
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Get a photo and post up in the normal technical section, and |
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someone will probably know what it is... |
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#Post#: 7790-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: Lucy Date: January 26, 2012, 2:53 pm |
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I'll add in some of the other bits I did... |
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Stripping my old box down now so I thought I'd open up the |
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transfer box and see how the 4wd system works... |
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This is the view in through the bottom cover of the transfer box |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/PICT40… |
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photo1 � Low Range |
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Here the transfer box is in low range. |
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Drive would come in from the main gearbox |
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http://ollr.10.forumer.com/viewtopic.php?t=3133&highlight=bit+gearbox<br |
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/>on the far right of this picture and is transmitted via the |
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intermediate gears in the middle to the output gears on the |
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left. |
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The following photo shows the transfer box in high range |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/PICT40… |
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/> |
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photo 2 - High Range |
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Sticking out of the front of the transfer box are 3 shafts |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/images… |
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photo 3 |
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The thickest one, at the bottom of the photo, is the front |
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output shaft, which transmits drive to the front axle when 4wd |
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is selected, at its left hand end you can see the dog teeth, and |
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the silver ring of the dog clutch that slides over them to |
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engage 4wd ( see photos 4&5 below. The one in the middle with |
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nut on the end is the high low selector shaft; this is connected |
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to the red lever. The top one is the 4wd selector. The bronze |
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coloured piece attached to it is the 4wd selector fork. |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/images… |
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Photo 4 - 2wd |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/images… |
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Photo 5 - 4wd |
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In between the hi/low selector shaft and the 4wd selector shaft |
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there is another short shaft |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/images… |
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/> |
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photo 6 |
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This is the shaft that allows 4wd in high range to be selected. |
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(the photo shows it in low range 4wd) |
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http://www.climbingchris.f9.co.uk/wilma/Wilma's%20gear%20box/transferbox/images… |
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Photo7 |
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The �L� shaped piece you can see is connected via a lever to the |
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yellow knob. As you push the yellow knob down it pulls the �L� |
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shaped peg in the direction towards the camera. This disengages |
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it from the short shaft and allows the shaft to move forwards, |
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pushed by the spring on either the hi/lo selector shaft or the |
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4wd selector shaft (can�t quite work out which), engaging 4wd. |
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When low range is selected the short shaft is pinned in place by |
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the 'L' shaped peg, so as the hi/low selector is pushed back, by |
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you pulling back on the red lever, the piece that is attached to |
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the short shaft by a pivot and runs between the hi/lo selector |
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and the 4wd selector pivots and pulls the 4wd selector forwards |
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engaging 4wd. This is illustrated in photos 4 and 5. |
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I think that's how it works. HOpefully it wasn't too boring and |
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anyone who knows better will be along to correct my errors and |
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clear up any unclear bits. |
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#Post#: 7791-------------------------------------------------- |
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Re: A bit about Gearboxes |
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By: Lucy Date: January 26, 2012, 2:54 pm |
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--------------------------------------------------------- |
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and a bit more to keep it in one place... |
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Rich was asking questions about gearboxes at the WWW yesterday, |
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and as I'm never one to stifel the urge to learn here's a bit |
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more about series 3 gearboxes. It's mostly applicable to series |
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2 boxes as well. I think the main differences (and please |
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someone who knows, correct me if I'm wrong) are that the series |
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2 box has square cut gears on 1st and 2nd and no syncros on |
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those gears. |
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Anyways, here's some piccies... |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 1 - Primary Pinion |
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This is the back of the input shaft (Primary Pinion) that is |
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driven by the clutch drive plate and goes through the Primary |
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Pinion bearing in the bell housing and has the Primary Pinion |
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gear on the back. Inside this gear sits the front bearing for |
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the mainshaft, the yellow cage of which you can see above. |
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Next on the inside of this gear you can see the dog teeth that |
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engage with the 3rd/4th syncro hub to take drive directly from |
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the Primary Pinion to the mainshaft resulting in a 1:1 straight |
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through drive for 4th gear. |
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Finally around the outside of the back of the gear is the syncro |
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cone that the 4th gear syncro hub sits over. You can see this |
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more clearly in the photo below. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 2 - Primary Pinion and Constant Gear |
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The gear on the left of the photo is the Primary Pinion, the |
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gear on the Right is the Constant Gear that transmits drive from |
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the Primary Pinion to the Layshaft. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 3 - 3rd/4th Syncro Hub (4th gear end) |
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This is the 4th gear end of the 3rd/4th gear Syncro Hub. |
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The brass coloured part sits over the Primary Pinion Syncro Cone |
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and the teeth around the outside of the middle part, engage in |
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the dog teeth in the back of the Primary Pinion gear as per |
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photo 4 below. |
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The splines in the middle of the unit engage with the splines on |
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the Mainshaft and transmit drive from either the Primary pinion |
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(4th gear) or, via the layshaft and 3rd gear, as per photo 5 |
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below. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 4 - Dog Teeth, Primary Pinion and 3rd/4th Syncro |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 5 - 3rd/4th Syncro Splines Engage on Mainshaft |
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This is the 3rd gear end of the 3rd/4th Syncro Hub, it has a |
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slight recess in the centre before the splined section (that |
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engages on the mainshaft) starts to allow for the 3rd gear |
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spring retaining clip to sit in. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 6 - 3rd/4th Syncro (3rd Gear End) |
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Below shows the layshaft, 3rd gear and the 3rd/4th syncro hub in |
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place. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 7 - Layshaft, 3rd/4th Syncro, 3rd Gear and Primary Pinion |
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This shows the layshaft in place and the mainshaft with all the |
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gears removed. |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 8 - Layshaft and Mainshaft, (Gears Removed) |
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next we have... |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 9 - Layshaft, 2nd Gear, 3rd Gear, 3rd/4th Syncro, on |
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Mainshaft, and Primary pinion |
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On top, the Layshaft with the Constant Gear on the right next to |
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the bell housing. On the bottom from right to left we have, the |
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primary pinion, then the 3rd/4th syncro hub, then 3rd gear, then |
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2nd gear. (there should be a brass coloured spacer which is part |
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of the bush that 2nd gear runs on between 3rd and 2nd, but it's |
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broken) |
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The shiney, smooth part of 2nd gear far left is the syncro cone |
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for 2nd (series 2 boxes will have -I think- a square cut 2nd |
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gear with no syncro cone on it) |
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[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
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Photo 10 - Layshaft, 1st gear, 1st/2nd selector/reverse gear |
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(square cut), 2nd Gear, 3rd Gear, 3rd/4th Syncro, on Mainshaft, |
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and Primary pinion |
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Now I've added the 1st/2nd selector unit (the part with a square |
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cut gear on it) and 1st gear. The square cut gear I mentioned |
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is the reverse gear, this engages with the square gear on the |
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layshaft via the Reverse Idler, which sits on a small shaft in |
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the back of the gearbox casing. |
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All of the gears that sit on the mainshaft (1st, 2nd and 3rd), |
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with the exception of the square cut reverse gear are free to |
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rotate on the mainshaft, and are constantly rotating whilst the |
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vehicle is in motion as they are turned by the layshaft. The |
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drive from all these gears is transmitted to the mainshaft, and |
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then on to the transfer box by dog teeth engaging with the |
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selector units (1st/2nd and 3rd/4th) which engage with the |
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splined sections of the mainshaft that you can see in photo 8. |
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In reality the layshaft sits underneath the Mainshaft, I just |
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turned the camera round the wrong way) |
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See also this thread |
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http://ollr.10.forumer.com/viewtopic.php?t=3133&highlight=bit+gearbox |
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and this one |
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http://ollr.10.forumer.com/viewtopic.php?t=3778&highlight=bit+gearbox |
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Sorry for the repetition of threads. |
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Now for jumping out of 4th gear... |
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It seems that the most common cause is broken detent springs on |
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the 3rd/4th syncro hub |
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[img] |
|
http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
|
/> |
|
[img] |
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http://www.climbingchris.f9.co.uk/wilma/Wilma%27s%20gear%20box/gearboxagain/PIC… |
|
The top photo has one spring present, on the left and next to |
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the post on the right the spring is missing, the second photo is |
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a close up of the detent spring insitu. (If your syncro hub |
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looks like this one though, you've got bigger problems than just |
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a broken spring) |
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There are 3 of these springs, one for each of the posts on the |
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syncro hub. |
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The part number for the springs is RTC1956. |
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hth Rich |
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Any questions, corrections or clarifications required let me |
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know. |
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Luce |
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***************************************************** |
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