Gearbox thoughts

[JJC]

I rebuilt the TR2 box a few miles ago and to my horror it's now making horrible noises in first gear. Just about to dismantle it (got it out of the car with help from a friend today) but thought it might be worth tapping a few brains before starting. I've done very few miles since the rebuild but have to admit those miles have been round Castle Combe, Goodwood and Mallory. At rebuild I replaced main bearings and layshaft and bearings, synchro cones but otherwise it was ok. I suspect the new layshaft. Any thoughts?

[Rhodri]

Is the oil clean? A grey colour may be layshaft, there are some poor ones about, I bit the bullet and got one from Revington. With the gear remote cover off you should be able to see/feel the layshaft cluster for play.

Edited April 6, 2008 by Rhodri

[pfenlon]

Only one way to do it strip it and measure your spacers etc, but suspect you will see the problem or feel it.

 

I got my spacers and bearings from Moss and had no trouble, but if you are doing track days, mods from the stag box may help with reliability.

 

Tony is your rally man who would know the detail.

[Tr4Tony]

Hi

 

Interesting that its happening in first .... normally id suspect thrust washers if you were booting around and downshifting fiercely, first probably means that there is something more fundamental with the mainshaft as you say ..... perhaps. Does it jump out ? or can you fish for gears ? this indicates things shuffling up and down the mainshaft.

 

Short of examining the oil for bits either silver (gears and washers) or gold (synchros etc.) and replacing it, maybe with thicker oil you probably have no alternative than to whip the box out and take it to bits ...... id suspect you may have some gear and or bearing damage as well if its making a lot of noise. It may be just that the bearings you were supplied arent up to the job and I have to say my own experience with gearboxes is that there is a bit of an art to building them well ..... which is why I just hand over the money to someone who can do it properly.

 

If you are going to do competition work my conclusion was that the stag a type box is the best alternative, save from a Toyota or Ford type 9 conversion. I talked this through with both Steve Hall and Neil Revington and there are merits in each depending on what you want to do. I plumbed for the stag a type as its 'original' and the ratio's are correct all the way through the box,and I have papers for BST82B which mean at least I need to make an honesty declaration that the car is 'period'. You may not see this as a constraint, in which case talk to Neil at Revington TR. His gearbox conversion is a proper job.

 

Regards

 

Tony

[JJC]

Tony - thanks for your thoughts. The oil is clean, no bits of any sort. Probably coincidence but the o/d slowed up in engaging as well. Understand your point about the art and fully agree. On the other hand I rebuilt a TR3 box (I just like doing it) for a friend who does lots of miles and he says his is fine. Maybe just luck but he did buy his parts from a specialist supplier. I also saw an article in my son's GT6 club mag talking about current parts which is what's worrying me.

Anyway, off to the garage to start dismantling. Do you know if it's possible to borrow the tool for putting the big circlip back on? The home made one is knackered after about four boxes.

Best regards

John