View Full Version : TR2/3/3A Question on reinstalling pinion flange on TR3A

01-12-2010, 04:54 PM
The 3A I am working on was mostly disassembled when I bought it - one of the things the previous owner had removed was the pinion flange on the differential. I don't have my manual in front of me, but I thought the procedure was to mark the position of the castellated nut, then reinstall in the same location. In my case - the 'same location' is the third cardboard box in the corner, not on the differential.

For setups like this with shim packs to set bearing clearances, would it be a huge mistake to torque the retaining nut to something reasonable and be done with it? How finicky are these setups when there is no collapsable spacer involved?


01-12-2010, 05:53 PM
If the same number shims are still installed, then 80-100lbs torque on the nut will be OK. I'd go to 100 then back off 1/2 flat until the cotter pin can be fitted. But if you've changed the shim thickness, maybe not OK.

01-12-2010, 06:08 PM
Just torque it down and put the pin in; if you are going to assume it already has the right number of shims and so on.

Unlike Peter I would sneak up on the slot, but that's just me, I don't know that it makes any real difference.

01-12-2010, 07:41 PM
put a new pinion seal in about 4k miles ago...used an air wrench and swagged the 80 to 100 lbs. (no changes internally to the rear end obviously) and no issues.

01-12-2010, 07:47 PM
Thanks - fairly certain the nut was removed just to change out the seal, cover is still on and it is still loaded with oil. So a seal changeout and inspection of the flange in case I need a speedi-sleeve and I think I'll just button it back up.

Geo Hahn
01-13-2010, 12:38 PM
I had a similar situation (no reference point) though in my case it was because when I went to undo the big nut it was only finger tight (though the cotter pin was in place). I had driven it this way for more than 25 years w/o any apparent problem, was just changing the seal to fix a minor leak.

I, too, just assumed that the shims were at one time correct and used the torque to reset the nut. So far so good.

01-13-2010, 03:44 PM
Been there...done that...lol. I recently rebuilt my entire differential when I installed a new ring and pinion. I would not call it "fun", but interesting nonetheless. The only way to be positively sure is to remove the differential cover and check the alignment/mesh of the crown and pinion. It should be no problem for you if the unit is out of the car, or even installed. This way you could also check the runout and flush out any gunk that may have accumulated in there. I'm using Swepco 201 (or210?) gear oil since it was recommended to me by a few guys. The stuff is incredibly sticky, more like sugar syrup than a gear oil, but it's supposed to be good stuff.

01-13-2010, 04:22 PM
Randy - did I read this right? Are you starting to dig into the TR3?

Go Randy, go Randy, go Randy!

01-13-2010, 09:10 PM
Randy - did I read this right? Are you starting to dig into the TR3?

Yep, but don't get your hopes up, I know I can stretch this project out for a long time!

I did manage to get the body off the frame, and I'm pulling the running gear off at the moment. I was slowed down a little over Christmas, I had intended to use a bare frame I'd been saving which was already blasted and pretty much ready to go - until I found the front turret was twisted by at least a 1/2". Game plan now is to work with the frame that came with the car which looks in great shape so far: