Gearbox dismantling question

Post by **ndevans** » Sat Oct 18, 2008 7:36 pm

Hello all,

I am in the process of removing the gearbox extension in order to get the tailshaft bush replaced. I am going to remove the gearbox whilst I am at it, and am planning to remove the extension first, then getting the rest of the gearbox out should be easier.

So far I have got the floor panel out, remove the propshaft and disconnected all the other bits and pieces apart from the clutch linkage. Next tasks are to jack up the front of the car to give me better access, remove the clutch linkage, and support the engine and gearbox.

I have two questions:

1 Do I need to remove the remote control, gearlever etc to remove the extension?

2 Does the gearbox extension more or less just pull away from the gearbox bellhousing when I remove the bolts?

cheers,
Neil
(also posted on the other board)

Post by **simmitc** » Sat Oct 18, 2008 8:42 pm

What year and engine/box size are you looking at? There are subtle differences between the boxes; but you will need to remove the gear lever to get the box out. However, that is very simple compared with the rest of the work!

Post by **rayofleamington** » Sat Oct 18, 2008 8:49 pm

it's many years since I did one, but from memory you will need to lift off the gearbox extension before you can pull the tailshaft casting away from the main box.
The gear lever linkage sits into a 'well' formed by the mouths on the end of the shift rods. Therefore it will only come off upwards.

Post by **les** » Sat Oct 18, 2008 9:55 pm

Ray's memory is good,the extension needs to come off first. Good luck with the bush renewal, you would do well to heat the casting before installing the new bush, and take care reaming it out, the bearing surface on the 2 bushes I tried was too thin and the reamer broke through to the steel back. 3rd was ok. If your bush is not too worn maybe think of leaving it. It's a pita!

Post by **ndevans** » Sat Oct 18, 2008 10:51 pm

simmitc wrote:What year and engine/box size are you looking at? There are subtle differences between the boxes; but you will need to remove the gear lever to get the box out. However, that is very simple compared with the rest of the work!

It's a 1969 standard 1098 engine & box.

Post by **ndevans** » Sat Oct 18, 2008 10:53 pm

rayofleamington wrote:it's many years since I did one, but from memory you will need to lift off the gearbox extension before you can pull the tailshaft casting away from the main box.
The gear lever linkage sits into a 'well' formed by the mouths on the end of the shift rods. Therefore it will only come off upwards.

Ray, by extension I presume you mean the remote control that the gear lever sits in?

So as I understand it, the gear lever and remote control need to come off the tailshaft casting before I can part the tailshaft casting from the bellhousing?

cheers,
Neil

Post by **bmcecosse** » Sat Oct 18, 2008 10:56 pm

Why are you renewing the bush - it very rarely NEEDS to be renewed - a new rear seal may be all that's needed.

Post by **ndevans** » Sat Oct 18, 2008 11:00 pm

bmcecosse wrote:Why are you renewing the bush - it very rarely NEEDS to be renewed - a new rear seal may be all that's needed.

I'm pretty sure it's worn. I have an oil leak coming from the tailshaft, I have replaced the oil seal which hasn't helped. There is sideplay on the front part of the propshaft, and it's a new u/j. There is no play in the u/j itself.

Post by **bmcecosse** » Sat Oct 18, 2008 11:04 pm

Hmmm - well - it's quite a job and you must have the correct size reamer. Slight oil leak here is quite normal - it helps to rust proof the underside of the car!

Post by **ndevans** » Sat Oct 18, 2008 11:07 pm

bmcecosse wrote:Hmmm - well - it's quite a job and you must have the correct size reamer. Slight oil leak here is quite normal - it helps to rust proof the underside of the car!

I had about a cupful from standing overnight!

There is an engineering firm near me who recondition propshafts & gearboxes-they will do the reaming for me.

Post by **bmcecosse** » Sat Oct 18, 2008 11:09 pm

Ahh - well yes that's quite a leak - and if they have the reamer and the skills - excellent!

Post by **ndevans** » Sat Oct 18, 2008 11:20 pm

bmcecosse wrote:Ahh - well yes that's quite a leak - and if they have the reamer and the skills - excellent!

Is there a particular size of reamer, or do you just measure the propshaft spline?

Post by **bmcecosse** » Sat Oct 18, 2008 11:26 pm

Well - it's the o/d of the propshaft where it enters the box + whatever running clearance you think is right!

Post by **rayofleamington** » Sat Oct 18, 2008 11:26 pm

Why are you renewing the bush

because it needs to be renewed... It wasn't the worst I've seen but if a prop UJ had that much play it would be a liability.

As for the size of the leak... losing 75% of the gearbox oil contents on an 80 mile journey is not good

Not only does it rustproof much of the underside of the car, it rustproofs the entire of the rear doors! That's something I learned from Land Rovers - you can check the gearbox for leaks by how much oil there is on the rear window

On a Land Rover it's ok, but on a traveller you don't really want gearbox oil in the wood as it'll fight agains the varnish next time round.

Is there a particular size of reamer

on the ones I had done they wanted the propshaft so they could make it according to the size of the mating part of the prop. This was done with an adjustable reamer.

Post by **ndevans** » Sat Oct 18, 2008 11:46 pm

rayofleamington wrote:
Why are you renewing the bush

because it needs to be renewed... It wasn't the worst I've seen but if a prop UJ had that much play it would be a liability.

As for the size of the leak... losing 75% of the gearbox oil contents on an 80 mile journey is not good
Not only does it rustproof much of the underside of the car, it rustproofs the entire of the rear doors! That's something I learned from Land Rovers - you can check the gearbox for leaks by how much oil there is on the rear window On a Land Rover it's ok, but on a traveller you don't really want gearbox oil in the wood as it'll fight agains the varnish next time round.

As Ray says, the rear of the car is now coated with a fine film of oil after driving from Bristol to Leamington & back. This was AFTER replacing the tailshaft oil seal!

Post by **bmcecosse** » Sat Oct 18, 2008 11:49 pm

Yes well - you did say it lost a cup overnight which is way excessive ! Of course - you have to wonder why it has worn like that - may be the bearings in the box (especially on the output shaft) are past their best - and maybe a wobble or wear on the propshaft has put undue strain on the bush ?

Post by **ndevans** » Sun Oct 19, 2008 1:27 am

I think I ran it for too long before replacing the u/j. I suspect the vibration from the propshaft has worn the bush.

Post by **bmcecosse** » Sun Oct 19, 2008 4:18 pm

And then in turn maybe the output shaft bearing inside the box - I would check it out, or perhaps just pick up another box and fit that! then fix this one at your leisure for a spare.

Post by **les** » Sun Oct 19, 2008 6:41 pm

1 1/8'' to 1 9/32'' adjustable reamer required, if you decide to go for it.

Post by **bmcecosse** » Sun Oct 19, 2008 8:20 pm

I have a note in my manual saying 1.118" is the size for the bush - but not sure where I got that from. 1 1/8" is obviously 1.125" - so measure the prop shaft first to make sure you don't ream the bush too large - although 7 thou on the diameter may well be a good running clearance!