I will try to keep this blog updated with my progress on my new project : a 1967 triumph spitfire mk3. Hoping this will help others and hoping I will get help as I would like to do things right.
Saturday, September 9, 2017
Triumph spitfire gearbox "almost" rebuild
Since the third gear would pop out as soon as you would press the accelerator and the linkage was ok, no choice but to pull the gearbox again out the car.
By the end of the winter I knew it was a good time to get started, less ski and keen to fix before summer ! Pulled the engine and transmission out in March 2017.
I had bought the gearbox and overdrive second hand, so I had 2 other spare gearbox, the original one from the car and the one from my parts car.
I was hoping to be able to swap the internals out, but as we can see from the photo below, they were not exactly the same.
Trying to recall what it took to open the box up, there are 2 tricky parts :
tricky part 1 : pulling the bearing out, see photo below you can use a small punch or build something like that
After that you slide and incline the main shaft to start getting the gears out. Keep everything in order !
tricky part 2 : trying to keep the needles inside the secondary shaft. Something was mentioned in the manual but I did not really understand why and where the needles were. See photo below, you see the shaft and the needles in the white cap. The trick is to insert a tube same length as the gear shaft while you take the real shaft out. If you fail to do this (like I did :-) ) you will wonder why there are needles at the bootom of the gearbox. If it does happen, make sure you don't lose any and are good for putting them back in one by one with grease. Not willing to sacrifice an old shaft, admire my temporary shaft made from an old broken nordic ski pole of the perfect diameter.
Once everything dismantled I was perfectly able to put everything back together but did not really know what is acceptable play or not to have a good working gearbox as well not 100% sure how it worked. I reached out to local French club "Rhone Alpes Spitfire" who put me in touch with Jean Louis, super nice guy with tons of spitfire experience. So one day I drove (2H) to go see hime and get a better understanding.
I put the parts back together held by wire and loaded them in my wife's car.
We looked at it on his workbench. It was great to talk face to face with someone with so much knowledge and he gave me plenty of advice. Most importantly he reassured me that this is not rocket science, just need to take it slow and think.
Once back home I methodically dismantled the 3 gearbox to get the best parts.
Mostly my problems were coming from 2 things :
- 1 ball and spring missing
- bronze bushings such as the one below completely worn out hence tons of play that lead to further issues.
Yes, you don't want to wait too long on these kind of jobs so you don't forget what goes where !
Finally it was back together on the bench and everything felt super tight !
Coupled the gearbox back with the engine
Fit back inside the car and pray !
In the end I did not have to buy a single spare part for this rebuild but almost everything is available for the usual resellers.
This took me a long time and effort but am so happy it works and can now enjoy third gear ! I hope this will help fellow enthusiasts to do the same rather than see this as a mystery black box.
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