Gearbox refurbishment advice.

[Rutty]

Has anyone got any recommendations as to who produces the best Gearbox refurbishment kit. My Mk1 2L is starting to whine quite badly in 1st, 2nd & 3rd so I suspect the layshaft bearings are past there best. I intend to have the box out over the winter and fit a refurbishment kit but I have heard that the metals used in some of the kits are not that great. Its an overdrive box if that makes any difference.

Thanks

Mark

[glang]

Apart from the needle bearings youll almost certainly need a new layshaft (hopefully the laygear and mainshaft tip surfaces will be ok) and its here that doubt exists. The shafts are case hardened and if not done properly the hard layer can be too soft or thin leading to premature wear in the area where the rollers run. I believe someone used to produce shafts with thicker case hardening but how long the usual ones (they all probably come from the same source) last really comes down to how much power youre going to put through the box, how many miles you do and how you drive.

You might also be tempted to replace the main ball race bearings but replacements of original quality are no longer available so unless yours are really shot I would reuse them....

[nang]

No disrespect intended but quite happy to rebuild engines and even  overdrives but I think I would give my gearbox to a specialist, which I did with my 2500TC.

Tony.

[Clive]

My friend Pete has built many boxes, and after a bad experience years ago with a layshaft pin that lasted 5 miles (yep, that was all) has so far managed to find good used pins to re-use. For some reason non-od boxes have a much easier life so are a good source of parts. 

I think the pin is common to later spitfire boxes as well as GT6/Vitesse? 

For bearings he uses a local bearing supplier, but buys proper brands only. Some bearings he re-uses, and keeps just about anything from inside a gearbox, though he is getting short of stuff now the supply is drying up. 

Moral is, find a good non-od box as a source of parts. Or maybe give Mr Papworth a call??

[glang]

Trouble is its difficult to tell from the outside which secondhand gearboxes have good layshafts. Also as all new shafts probably come from the same supply most professional gearbox refurbishers will be using them as well. Of course there should be a guarantee but for most of us our annual mileage is quite low so it will run out long before the gearbox has covered the distance we would hope for....

[Rutty]

Quoted from nang-

No disrespect intended but quite happy to rebuild engines and even  overdrives but I think I would give my gearbox to a specialist, which I did with my 2500TC.

Tony.

Interesting comment as everyone else I have spoken to has said they would rebuild the gearbox but give the O/D to a specialist. I understand the triumph gearboxes are very simple and looking at the manuals and online it would seems to be the case. Thanks for you comment all information is gratefully received.

Thanks

Mark

[Rutty]

Quoted from cliftyhanger-

My friend Pete has built many boxes, and after a bad experience years ago with a layshaft pin that lasted 5 miles (yep, that was all) has so far managed to find good used pins to re-use. For some reason non-od boxes have a much easier life so are a good source of parts. 

I think the pin is common to later spitfire boxes as well as GT6/Vitesse? 

For bearings he uses a local bearing supplier, but buys proper brands only. Some bearings he re-uses, and keeps just about anything from inside a gearbox, though he is getting short of stuff now the supply is drying up. 

Moral is, find a good non-od box as a source of parts. Or maybe give Mr Papworth a call??

Thanks Clive for some great advice. I have a None O/D box that came with a load of other spares when I brought the car. The owners son told me he stripped it out of another Vitesse he brought for spares. I hadn't appreciated that the layshaft and other parts would be the same.

So is it only the mainshaft length that is different between O/D and none O/D boxes? 

So my first job is to strip down the none O/D box and inspect the parts. I am not sure quite what I am looking for regarding wear but I guess it will be obvious once I have the box stripped down.

Thanks

Mark

[glang]

Youre right they are relatively simple but thats all related to your ability of course....

However, although a replacement of the layshaft is straight forward enough, if you want to check and correct the various clearances as per the workshop manual its a little bit more involved and may require the substitution of components (some of which are now not available new) which is where a specialist should have an advantage.

The gearbox may work ok with incorrect clearances but they can add up to give a poorer gearchange and noisier running.

[Richard B]

I wonder if its the side load of the O/D oil pump on the mainshaft that makes those boxes more problematical?

I also trust Pete with my gearboxes.

[RobPearce]

Quoted from Rutty-

Quoted from nang-

No disrespect intended but quite happy to rebuild engines and even  overdrives but I think I would give my gearbox to a specialist, which I did with my 2500TC.

Tony.

Interesting comment as everyone else I have spoken to has said they would rebuild the gearbox but give the O/D to a specialist.

Well, I'm with Tony on this. At least, I've rebuilt four or five engines and two overdrives but no gearboxes. They've always gone to a specialist.

 

[glang]

Quoted from Richard B-

I wonder if its the side load of the O/D oil pump on the mainshaft that makes those boxes more problematical?

Or Ive always wondered if it could be down to the shorter mainshaft and poorer support it has in the OD unit....

[thescrapman]

I have rebuilt 3 gearboxes over the years, all small saloon. The PI box went to a local expert who did a spot-on job, just because he offered at a good price.

only OD work I did wasa "do or die" flush out with petrol I think it was to try to remove the debris from a chewed up mainshaft tip bearing. It worked.

I did have the mainshaft and input shaft machined on that box and a caged bearing fitted as restseemed OK.

[RobPearce]

Yeah, in fairness I should confess that the first O/D I did was because the gearbox expert (who didn't do overdrives) returned the two parts separately with the comment that the OD was "probably scrap, judging by the amount of aluminium swarf". I figured, if that was the case, where's the harm in stripping it? And I found that somebody had previously attempted to refurbish it but hadn't been too hot on cleanliness, and (fortunately, in a way) had broken the oil pump. New pump, clean up, reassemble... one pretty much perfect overdrive.