Gearbox questions

[StagnJag]

Hi all,

One of the jobs I am thinking of tackling this autumn is my manual gearbox. It should generally be in good health as it was only re-built around 3 years/20,000 miles ago, but 4th to 3rd and 2nd to 3rd crunches like mad. I need to start putting together a shopping list. I would be grateful if you could give me some pointers as to which bits I am likely to need. Not all bits are available new from the usual suppliers so It might take a little while to gather the bits I need together.

I know it would be easier to buy a reconditioned one, but I like a challenge. (Although if it all goes pear shaped Kryten might get a visit from me carrying a box full of bits!).

Cheers

Dave

[NickA]

Last time I did my gearbox I just replaced all the bearings and left the syncros alone but from what you're describing you may need to change the syncros as well. Wasn't there some issues with the qualify of the aftermarket syncros? 3 years and 20,000 miles doesn't seem a lot of miles for a recon gearbox!

There's also a really good article on gearbox overhaul in the Practical Classics Stag Restoration book. If you want a scan PM me.

Cheers

Nick

[StagnJag]

Hi Nick,

thanks for the tip on the gearbox article, I've got that book somewhere.

I have noticed that Rimmers offer two sets of Syncro rings, one being a high quality set. Is the bit the syncro rings mesh with likely to be worn as well? Especially given that i have been crunching my way through the gearbox for many 000's of miles now!

Cheers

Dave

[Arbman Al]

Hi Dave

Dasadrew is your man to talk to as he has just done his. His thread has some info about parts I think.

Al

[StagnJag]

Hi Al,

I actually posted this question on his resto post and he suggested that I create a new topic which I now have! hopefully Drew will be along shortly!

Rgds

Dave

[Firept]

Dave. before you do anything try this oil http://www.halfords.com/webapp/wcs/s...egoryId_255220
Its SX75-90 GL4 any version same spec will do but it makes a big difference to how the box behaves may save a rebuild until later.


Paul.

[dasadrew]

The first tip I have is to start scanning eBay worldwide as soon as possible. A lot of the gearbox parts I needed I had picked up over the last three years on eBay - sometimes USA, sometimes Australia! I must admit that I check eBay UK every morning when I get up (06:30h German time; 05:30h UK time!) I've picked up quite a few Buy-it-nows that way. I got a set of NOS Synchro Rings off eBay too and I've seen some more on eBay since then as well.

For gearbox parts, remember that 95% is common with the TR6 for which there are many more suppliers. I got a lot from Revington TR. Also, Chris Witor has quite a few good bits if you know the part number.

The most fabulous book for the gearbox I found to be the Unipart Triumph Stag workshop manual. It's got all of the stuff of the official ROM but is somehow easier to follow on the workbench. Obviously, get the Gearbox stuff downloaded off Buckeye Triumphs too.

Spacers and bushes can be a pain to get the right clearances. You need also to find out what gearbox you've got as the spacers are different. Best clue is a little steel ball which fits into a recess in the mainshaft and engages into a cut-out in a special spacer. This is the "definitive" Stag "late" gearbox. There was an "early" gearbox and it seems that there was even a "very early" gearbox for the first couple of hundred Stags. My box was a Frankenbox and had early parts in a later case.

For good exploded pics, try also the books (I think they call them blue book or something like that) on the Triumph Roadster Factory site in the USA.

All of my gearbox bearings came off very easily without any special tools. To put the bearings back together, however, I needed a plate with a bolt and nut (pics will follow).

The circlips were a big disappointment and I ended up ordering from 2 or 3 suppliers before giving up. They were all thinner than the originals and I was faced with the choice of using new ones which would flap about in the groove or using the original old ones. I plumped for using the originals but only after I was really confident that they still had enough spring in them and no excessive scoring. Not the best I know.

There is one retaining clip - 55707 - which causes cursing across the planet at the front of the layshaft. A real pain to get off - mine looked like a corkscrew when I was finished. I fitted a new one and that is a pain too. The circlip has to be drastically expanded to go over the splines and, when it arrives in position, it had lost a lot of springiness and didn't want to fit tightly into the groove. Shock Horror! I managed to squeeze it together a bit and I just hope that metallurgical creep will return it in time to its small diameter although again I am not without sleepless nights on that.

The needle roller bearing 150989 seems to be an oddity. The parts catalogues show one in the rear of the input shaft and one at the rear of the layshaft. When I took my gearbox apart, there were two in the layshaft and none in the input shaft !!! I've not seen a single parts diagram which shows two in the rear of the layshaft but the actual depth of the bore seems to provide enough depth for two. Hmmmmmm..... When I read the workshop manual, it says to insert TWO needle rollers into the layshaft. So it looks like you actually need three 150989's. My layshaft was correct, but I can hardly believe that the gearbox worked without an input shaft bearing! I guess the guy doing an overhaul had only ordered up two and fitted them both to the layshaft.

When the casing is stripped, don't forget to check all of the bolt holes and Helicoil them if necessary.

I'll post more bits and pics as they occur to me. I'm on the top cover / selector mechanism at the moment.

Drew

[Mike Stevens]

There is one retaining clip - 55707 - which causes cursing across the planet at the front of the layshaft.

Sorry to be pedantic, but do you mean mainshaft here? If so, there is a special Churchill tool for this circlip, but having borrowed one in the past, I can assure you that it didn't make it much easier!

I agree. These gearboxes are not difficult to work on. I've done a number of saloon ones before as well as the Stag one. Funnily enough the early Haynes manual for the saloons is very good for this work.

Cheers,
Mike.