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Triumph TR6 - Leaking Gearbox

My recently rebuilt gearbox (with OD) on my '76 is leaking and because of the layout with the exhaust it drips on the pipes and I start smoking when sitting at long lights. It is driving me crazy (besides being a hazard)so I want to do whatever to get it right. When I rebuilt the gearbox, I used the gaskets from TRF but did not use any gasket sealer like Permatex. Should I have used that? And if yes, what type. Also, I have a hard time seeing where the leak is coming from. The front and back oil seals are new so that is not the problem. I saw on the 6-pack BBS that someone had a similiar problem and wiped the whole unit down and put talcum powder on the gearbox and then took it for a short drive, said he was able to see the source. Does this or something else work better. The last thing I want to do is pull the whole unit out. Any help would be appreciated
Mike
Mike Parkhill

Mike,
You will need to "pull her out"! Yep, the transmission! Next order a set of gaskets from Moss, I like theirs much better because they are thicker and therefor can seal better. I definetly recommend a gasket sealer on all of the gaskets. For the transmission and overdrive I like to use Permatex #2 (non-hardening) Dry gaskets do nothing but wick the oil right out of the case. I also use sealer on the rear oil seal. Also check the o-rings for the shift fork shafts, they go bad and leak a lot too. These transmissions really like to leak at the overdrive adaptor plate mostly on the overdrive side so make sure to coat that gasket with a good amount of sealer. When I rebuild transmissions here I run them on the bench for an hour and any leak is fixed.
Steve Yott

If someone reasembled the O/D without taking care, he may have cracked the adaptor plate between the gearbox and the O/D. A new gasket or Permatex will not fix that. Only a new adaptor plate will.

Don elliott, 1958 TR3A
Don Elliott

Did you fill the tranny with a synthetic? Some of these are drippier than good old oil.
Ignatius

Don't overlook the tiny seal and o ring in the speedo drive - very easy to change, but being at the bottom, is a good leaker. I like the talcom idea, a good one. There are also the leak finder dyes that show up under blacklite. Whatever works. Peter G
Peter G

Never - Ever, use synthetic oil in your gearbox with or without overdrive. It is so slippery, your synchros will "feel" no friction, so the won't work and you'll think your gearbox suddenly became a 1920's crash box before synchos were invented. Also you'll find out that you're always slipping out of gear.

In fact, a TR racer used synthetic in his racing TR and it came out of gear on a hard curve. The car rolled and he had to scrap it after he rolled.

When other race drivers got together to talk about this, they all reported the same curious problems.

They drained the synthetic oil, put in what they had been using before and the problem was solved. But not for the poor guy who rolled his. Luckily he was not injured.

Don Elliott, 1958 TR3A.
Don Elliott

Thanks for the input. I might as well pull the whole unit out and do it right. I thought about those o-rings on the shafts, I did not replace those so they are original and are probably part of the problem. Because of previous threads on the subject, I use StaLube GL-4 in this gearbox and the one in my tr3a.
Mike
Mike Parkhill

I just thought of another question. If I use gasket sealer like Permatex, do I still need the paper gaskets? What use would they serve?
Thanks
Mike
Mike Parkhill

Mike,
Yes, use the gaskets with the Permatex #2. I have had very good luck with this combination. On "A" type overdrives I also use a very thin coat of Halamar on the brake ring surfaces to help seal those, even though the book says to not do this. I have not had any problems with it, but keep it thin! As far as oil, I use Mobile 424 "tractor transmission and hydraulic oil"!!!! You can buy this in 2.5 gallon containers for about $25.00. This is an 80 weight GL4 fluid that works great for both overdrive and non-overdrive transmissions. If you can find the Stalube GL4 from CRC, that is great stuff too but becoming rare around here.

Steve
Steve Yott

I use the 'Redline MT' (Manual Transmission), definately synthetic, and the shifts are as smooth as silk (Non Overdrive), supposedly designed for our kind of boxes.
And my favorite sealant is 3M Anearobic (now Permatex, I believe) Need very little, gives you all the time in the world to assemble and does'nt go off till air is excluded,IE, tightened down.And comes apart again, if you need. Peter G
Peter G

This thread was discussed between 17/03/2003 and 20/03/2003

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