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Triumph TR6 - differential oil seal

I recently topped off the differential in my '74 TR6. I filled it until it ran out of the fill hole. After it finished draining out I then put the plug in. Now I find that the front seal leaks and blows back. I have read on previous threads not to mess with the front seal. There is a collapsable spacer that fits behind the pinion bearing. My thoughts are to replace that spacer, a new seal along with a new nyloc nut and torque to specs. Has anyone done this before? If so what are the torque specs I need to know?

Mark-This issue comes up quite often. According to Moss and TRF the change to the collaspsible spacer was made in 72, but many people with later cars still have the solid spacer. If the pinion has a castellated nut with a locking wire it probably has the solid spacer. However, a PO could have replaced the nut with the nylock type used with the collaspsible type. If the collaspsible spacer is over-torqued the bearings can self destuct from excessive pre-load. In order to replace the spacer, I think it is necessary to disassemble the diff. The safest way to deal with it is to mark the location of the pinion nut (also the number of threads protruding from the nut) before removing it and not torque it beyond the mark when it is replaced. Needless to say, the diff has to be removed in order to replace the seal and one thing will lead to another. Such as drilling&tapping for a drain plug, replacing the axle seals, checking the diff mounts and u-joints, and other fun areas. It is always something.

I recently had the front pinion seal replaced, twice. The first seal installed was the one supplied by Moss and it simply didn't work. The next one was supplied by British Motor Sports in Toronto (905) 678 6479 and it works fine. It is a polymer seal with a single spring circlip. I knw the trouble you are going through and if yoou don't get that seal fixed, you will have to top up your diff. every 100 miles or so.

NAPA seal 15207 works great. MOSS seal is 'original' type IE leather and can never be expected to do a good job.
Re changing it, a 74 should have the non collapsible spacer so it is very easy. The collapsibles are easy too, I've done hundreds of them on all kinds of cars and the trick is to very carefully mark EVERYTHING before you start, Mark the relationship of the nut to shaft with a tiny chisel (for accuracy) AND the relationship of the flange to spline (taking no chances here). On reassembly, make sure everything goes back precisly as it came apart then tighten manually to your marks (NO impact gun OR torque wrench here). It will be exactly as before (except no leaks).Never had a diff failure yet.

Peter 74 TR6
Peter Gooch

Thanks for the tips guys. A friend whom I met on here, suggested I post this thread. Now that I have some positive answers I think it's time to operate. ( slowly )

Where is that front seal? My 71 TR6 has belonged to me for only a short time--when I had it checked over initially, there was a differential leak and the guy was supposed to fix it. But there is a leak somewhere under the front, toward the rear of the engine compartment, I think, and it doesn't appear to be engine oil. And, how do I check the diffential fluid level and top it off?

So much to learn, but at least it's interesting!

Thanks, John.

John, if you follow the drive shaft back, the differential front seal is directly behind the flange the shaft bolts to. Any leak is obvious. Checking is a bit of a fiddle as the plug halfway up the back of the unit on passenger side, I think, is somewhat obscured by the exhaust. Good news is you don't need to check it hardly at all UNLESS you have a leak.

Peter 74 TR6
Peter Gooch

This thread was discussed between 28/08/2003 and 30/08/2003

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