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Triumph TR6 - Leaking differential

I noticed oil on the garage floor beneath the differential on my 76 six. On inspection, it looks like the oil is coming from the front oil seal, near the main drive shaft. I assume that I need to pull the entire rear axle assembly and rebuild the unit. Is there a way to replace the seal while the unit is still on the car and would this make any sense? If I decide to do the rebuild myself, will I need any special tools? Any help anyone can offer would be appreciated.
Mark Hauck


You might check to make sure the differential case vent is not blocked by oil/road grime. It's on the top right rear of the case and is a split key in a hole. Don't pull it out. Just make sure it is clear to vent the case. Understand this can case heat/pressure build up in the case and cause the front seal to leak. May save you a headache!

MAC Calhoun

As for replacing the seal I'm sure the the diff has to come out...might be a good time to do the others as well
Charlie B.

Mark-Replacing the pinion does require removing the diff, as well as the opportunity for doing a lot of other stuff since you have it out. Might as well replace the axle seals, drill&tap for a drain plug, check the area around the mounting studs for cracking, probably replace the rubber mounts,and check or replace the u-joints. Also check the exhaust system, since most of it will have to be removed to get the diff out.
Most likely you diff will have the collapsible spacer if it was built in 75 or 76. To prevent over torquing the pinion nut and having to dissassemble the diff or risk damaging the bearings, scribe a line on the pinion nut and flange before loosening. Then when tightening the nut, don't go beyond the scribed mark.
You will find a lot of good info on removing the old pinion seal and other details in the archieves.
And all you wanted to do is fix a little oil drip.
Berry Price
BTP Price

Mark The Pinion oil seal is a very easy job, It is possible to do it without removing the diff but I would go the same route as I did last weekend and take it out. It only requires unbolting the prop-shaft and the 2 drive shafts and 4 securing bolts to the frame and its out! (its very heavy!) Remove the input flange and the seal is very evident and can be removed with a large screwdriver or pry-bar, Just tap the new one in keeping it level and square, the most difficult part of the job is getting the pinion flange nut undone and tightened up, If you have access to a compressor the best way is an air impact wrench, and when it comes to tightening it,do the same Good luck
Clive P

Berry I have just read the last post again and did not know that the later cars had a collapsible spacer between the pinion bearings which would make the air impact wrench a good idea for removal but not for reassembly, either way It is not a bad job to undertake, The idea of makeing a mark to retighten is good, but the bearings will have lost most of their pre-load over the last(who knows how many years) or miles. If they still feel good give them a little more on the wrench! just a little.
Clive P

since the diff is out don't forget to replace the mount bushings....poly is very good.

Clive-You have my respect and envy if you can change the pinion seal without removing the diff. Access is very limited by the drive shaft& tunnel. Every seal I changed has to be thoroughly destroyed with a screwdriver to get it out. Instead of an impact wrench, I prefer to make a flange holder from a metal bar or maybe wedge a large screwdriver between 2 of the bolts.
Moss&TRF list the change to the collapsible spacer at about 1971-72, but many people have later cars that still have the solid type. I think they can be identified as to the type of pinion nut used. The solid spacer type used a castellated nut with locking wire, whereas the collapsible spacer was used with a nylock nut.
Berry Price
BTP Price

Thanks guys. After reading this string of responses, it's like I have already done the job before. Your collective knowledge is just incredible. This site is an invaluable asset. Thanks again for taking the time to respond.
Mark Hauck

Berry I totally forgot that when I said the seal replacement was possible with the diff in the car that I had the prop-shaft removed. I stand corrected.My car is 74 and has a solid spacer so the originality of the diff is a little suspect!
Clive P

Clive-Thanks for the explanation as I couldn't picture enough room to use an impact wrench or remove the seal with the drive shaft in place. Maybe removing the drive shaft would be easier than removing the diff.
I think the type of spacer used was whatever was available until the last year or two of production.
BTP Price

This thread was discussed between 30/04/2005 and 02/05/2005

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