soontobered84

Yeah okay. This is yet another reason I don't work on airplanes.

I replaced the replacement transmission/diff with another replacement transmission/diff. Somehow, in the throes of the second replacement, I forgot to fill the basically empty diff with lube. It's a PSD car and the "carrier" bearings basically seized as I pulled into the parking lot of the hotel in Rockport during Spring Fling.

I had the car flatbedded to Tony's shop and we put it on his lift (Thanks again T). We removed the left half shaft connection from the diff and drained what was in the differential (about 3-4 oz of gnarly looking ooze, but no pieces of parts)

We removed the left exhaust to better access the differential fill hole and added a bit of gas (It's what we had on hand) to wash the gears et al. We managed to turn the gears inside the diff and then drained what we had put in. Still no pieces of parts. Maybe not such a bleak outlook?

I started the engine, put it into gear and released the brake and the bearings started squalling like a baby as the flanges began to move. Ok, the bearings are toast as I suspected.

I flat-bedded the car to North Texas.

I have removed the flanges on both sides. The differential has a bolted in place plate on each side of the differential. Do I access the bearing from behind that plate? Or from inside the main rear cover?

My plan is to lower the differential to enable me to remove the rear cover to see what I really have back there and also to clean the ooze inside.

Any hints or helpful insight would be greatly appreciated.

ammonman

The carrier bearings are tapered roller bearings same as the wheel bearings just bigger. Those "plates" on either side contain the "cup" half of the bearing while the "cone" half is pressed onto the differential itself. You will need to remove both of the carrier plates and the differential unit from the diff case to replace the bearings. There are shims between those carriers and the diff case. Don't mix them up as they are part of what sets the backlash between the ring and pinion (there are also shims behind the pinion bearing case.) You may also need to replace the small spider gears and their shaft as they don't have bearings instead relying on close tolerance and lubrication. Sorry to say I think you are going to get another opportunity to remove the trans as I don't think you can get the differential out of the case with the trans installed in the car. It might be possible if the exhaust and fuel tank are removed but I don't know for sure.

Mike

GregBBRD

It happens.....

Take the transmission out.

The ring and pinion (and pinion bearings) are bound to be junk, also. The seal that separates the differential oil from the automatic transmission oil will be cooked.

Hopefully you still have the original transmission, so you can harvest the pieces from that transmission.

You will have to set-up the pinion depth onto the new transmission, as well as the differential preload and backlash.

Not many mechanics have the skill set and tools required to do that job....

docmirror

I was hoping that the pinion bearing and seal would be salvageable. Maybe not, because I haven't been that deep into one before.

I can set the pinion depth, and backlash once the parts are there. I think with the help of the books, we can swap the pinion with a new seal. The backlash isn't a tough job, just a bit time consuming.

It will live again.

GregBBRD

Terrific that you've got it under control!

docmirror

Let's hope. We're not even inside much yet. I'm surprised the cooked seal didn't allow ATF to migrate into the diff area. I'm going to go over next week and have a better look.

The left bearing is had it for sure. I took the axle off the left side(ring gear thrust side) and it was pretty frozen. The right side would turn a bit, but very stiff, which could indicate the spiders are cooked, but we'll know more once we have a better look.

soontobered84

Thanks for responding Mike, Greg and Doc Mirror. I was hoping to avoid taking the transmission out again, but I'm getting so good at it now, maybe it's not that big a deal.

It might have to wait an additional week since BradW is reroofing his house due to softball size hail. Lots of stuff normally in his garage is now in his shop and he's also dealing with a butthead adjuster about his black 928.

Greg, I do have the original and the original replacement transmissions, so I guess I can pick and choose. The original transmission has 220K miles and the original replacement has 30K+ miles but was in a front engine car fire. I didn't notice anything inherently wrong with the diff in the 2nd transmission, but there was lots wrong with the transmission itself. I suppose if I'm replacing bearings and seals, it really shouldn't matter?

Thanks to all of you in advance for any continued input.

soontobered84

To close out this thread: I cooked the diff in the second transmission since I didn't put any lube in it and drove to Rockport. I sourced another diff from the original transmission and installed it with a lot of help from Simon D. and Mike H. at BradW's workshop. Thank you all for your guidance and help.

soontobered84

Sorry it took so long to close this thread. I thought I had updated it.