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Fitting Overdrive to Gearbox

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M

mylesw

Jedi Hopeful
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Hello

I removed the overdrive from my gearbox (whole) and am now trying to refit it. Each time I try to mate the two together, the overdrive hangs up about half an inch from the gearbox backplate and I am unable to get this gap to close. This happens with and without the cam in place. What is the trick to doing this?

Thanks

Myles
 
Get a really bright torch and look down into the OD at the two spline sections. They should be in alignment, otherwise the gearbox shaft won't go into the sprag clutch spline at the back. I forget now whether you have to align them perfectly first by eye or if it can be done by wiggling the output shaft when lowering the OD.

Andy.
 
57_BN4 said:
Get a really bright torch and look down into the OD at the two spline sections. They should be in alignment, otherwise the gearbox shaft won't go into the sprag clutch spline at the back. I forget now whether you have to align them perfectly first by eye or if it can be done by wiggling the output shaft when lowering the OD.

Andy.
Click to expand...


Just in case: "torch" is a flashlight (no need to fire up the oxy-acetelyne rig).

I believe the shop manual has a procedure for doing this; IIRC it involves dropping the gearbox onto the O/D vertically (after aligning the splines).
 
Had a look into the OD and it looks like the splines are misaligned by a few mm. How do I realign them...?

Thanks for your help.

Myles
 
The workshop manual calls for a dummy shaft but I'd reckon a big screwdriver and some patience would do equally as well.

copy of workshop manual here if you don't have one
https://www.yousendit.com/download/T2dmaUNLeFg3N0RvS3NUQw

PS why did you pull the OD off? If you happen to have replaced the gearbox synchro rings with reproduction ones then they will almost certainly not work unless they were lapped into the mating gearbox cones. I now have to re-disassemble my gearbox to do this as I have no 3rd or 4th synchro action.

Andy.
 
If you do not have a 'dummy shaft' , take a very long #2 flat blade screwdriver and spin the one-way clutch teeth counter-clockwise (I believe) until both sets of teeth line up. There is little room for error so make sure the screwdriver does not drag on on either side of the teeth once lined up. I guess you already know about the oil pump eccentric as it relates to the pump. It can cause the two not to mate but does major damage if forced together.

Alan T
 
As mentioned the cam may be keeping you from alinging the shaft, it pushes the shaft to one side. I used a fine wire to hold the cam away until I was able to align all, don't forget the shims. It's possible the mating surface has been "nicked" from someone forcing the shaft in.
 
All of the above.

I found a used output shaft on Ebay for abour $40.00, and my plan was to "point" the ends to mimick the factory tool. Turns out that all I have to do is insert and rotate it to get the two (2) splines to line up, then it can be easily dropped onto the gearbox.

In the past, I would rebuild the OD first, so I could use the shaft to align the splines, and then put the OD where nobody could mess with it until final assembly.
 
Thanks for all your suggestions. I'm trying to turn the splines with a screwdriver but they won't budge. Should these turn easily or am I not trying hard enough?

Myles
 
Thanks, that worked! Overdrive is now back on...

Thanks all for your help.

Myles
 
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