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TR4/4A Replacing Drive Train Seals

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TBU_Triumph

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We're continuing our rejuvenation efforts on the 1966 TR4A. Overall it is in decent shape for a 50 year old car with 70,000+ miles.

I am debating (or arguing) with myself if I should replace some key seals in the drivetrain. Specifically I am looking at the transmission input shaft and output drive flange seals as well as all 3 seals on the differential (IRS car). The only ones that show signs of leakage right now are the differential input shaft and the right side drive flange.

Based on experiences form forum members am I creating more problems by replacing them or should I leave those that are not leaking alone? My concern is not the level of skills or tools needed to do the work. We have that well covered. Plus the transmission is already out of the car and the diff will be in a few weeks.

Thanks,
Rusty
 
TBU_Triumph said:
We're continuing our rejuvenation efforts on the 1966 TR4A. Overall it is in decent shape for a 50 year old car with 70,000+ miles.

I am debating (or arguing) with myself if I should replace some key seals in the drivetrain. Specifically I am looking at the transmission input shaft and output drive flange seals as well as all 3 seals on the differential (IRS car). The only ones that show signs of leakage right now are the differential input shaft and the right side drive flange.

Based on experiences form forum members am I creating more problems by replacing them or should I leave those that are not leaking alone? My concern is not the level of skills or tools needed to do the work. We have that well covered. Plus the transmission is already out of the car and the diff will be in a few weeks.

Thanks,
Rusty
Click to expand...

I replaced mine and I'm glad I did. The originals were rock hard/brittle.
 
I'm usually with the "if it ain't broke" crowd, but IMO if the transmission is already out (and still has original seals), it would foolish not to change them. They're easy to change (with it out of the car) and modern seals are almost never defective. Check the surfaces that the seals run against too, sometimes the original seal has cut a groove that can cause a new seal to leak. If you can't polish away any marks, consider installing a Speedi-sleeve.
 
Thanks for the guidance. I definitely will replace the diff seals. It is pretty much coated with grease and crud. The car has been sitting quite a while so I expect that will start leaking more when it goes back into service.

I'm still debating about the trans but am leaning towards doing it just because it is so little work right now. It is obvious that the transmission has been out of the car but we suspect that was for a clutch job. Whoever did that work hammered on the end of the output shaft (not sure why) so much that I will have to remove the burr to remove the nut.

And thanks for the reminder about polishing the sealing surface. There is one trick I have used successfully when the old seal has cut a groove in the shaft. If there is room in the installation I will install a spacer ring in front of the seal so it runs behind the prior position. You cannot always do that do to the space limitations.

Rusty
 
Full speed ahead I says. I think 50 years is plenty before they need to be taken right down and built back up. That way you'll get a closer look at the u joints , mounts , exhaust etc.
 
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