Paul902

Unseasonably warm today so I set about to remove my rear differential. Drained fluid, unbolted halfshafts from the halfshaft flanges, moved halfshafts out of the way, and unbolted the differential side cover.

How do I prevent the diff from turning as I remove the large bolts that hold each halfshaft flange to the diff internals?

Once these bolts are removed, is there a trick to remove the diff side cover so that the diff does not fall inside the bell housing, possibly damaging the bearing?

thanks.

viperbob

Boy you are ambitious today. The stub axle bolts in the center do not have very much torque on them. They should unbolt easily. Worst case, use a couple of bolts in the stub axle holes and use a prybar between them to hold it still. Be careful removing the diff cover. The diff unit should stay in place inside the housing when you remove the cover. But be ready in case. You won't damage the bearings.

Paul902

Thanks Bob! I am spending the afternoon taking care of my sick g/f but I'll give that a try tomorrow.

Paul

Paul902

The LSD came out with no problems! I'm happy to report that the bearings, races, and ring and pinion gears are all looking to be in excellent condition. Pics attached....

Now, what's the best way to go about opening the LSD? After pulling the bearings off, does one need to make a jig to prevent the case from turning while you remove the large bolts? What are their torque value?

993Porsche

Just wondering why you're removing your diff?

Ken

Steve Weiner-Rennsport Systems

Paul:

I use some soft jaws in my bench vise to grip the LSD without damaging it.

Then, you can remove the ring gear bolts, lift off the ring gear, and expose the screws that hold the LSD together.

Garth S

Paul,
Perhaps a dumb question, but do the bearings have to be pulled as you mentioned? I've only done the Ford type - and the bearings stay on for a simple clutch pack rebuild. Just the ring gear departs ...

Paul902

My limited slip friction plates are worn out so I am in the process of replacing them.

Paul902

Thanks, Steve. I'll look at that approach. I am not sure if my bench vise is large enough to accomodate the diff, but it would be a good excuse to get a bigger vise.

Does that mean, as Garth S suggested, that I can remove the ring gear and disassemble the diff without removing the bearings?

Toga

Interesting!!
Paul please, keep up posting more pics so we can follow your work.

chris walrod

Another option for holding the diff is using the drive flanges to hold it while working on the assembly.

I have attached few images to show how --

Keep in mind these are racecar parts I have used to illustrate this, but they are essentially the same with the exception of the bolts thread-into the 993 flange, and not the racecar flange. You'll just have to turn the bolts around.

Use the other drive flange to hold the -free- side of the diff in a similar manner, only you'll have to use some sort of a cheater bar, placed between the bolts.

Paul902

Chris,

that's a slick idea! Thanks for taking the trouble to take some pics of what you mean. I should be able to do it that way.

I am still wondering if I need to pull the carrier bearings off each side of the diff or if I can leave them on in order to get the diff apart.....Can anybody tell me that?

Garth S

See WSM 39-6, hidden in the 2wd G50 section for a description of the open diff .... no apparent info on the LSD. The ring gear bolts are in @ a snug 148 ft-lbs; however, the spyder gears on the open unit can come out with the ring gear in place as well as the carrier bearings. I could not find any WSM info on the LSD .... do you have a side view pic? That could clarify if/how the ring gear obstructs the access to the internals.
From the two pics, it does appear that the LSD unit is bolted together in a circle outside of the carrier bearings. I would still think that the carrier bearings can stay in place. This would be good, as they are shimmed behind for gear lash, and are susceptible to damage when removed. ( BTW - the carrier bearing cones are ID'ed to their respective cups for correct reassembly ...right? ).

chris walrod

The ring gear must come off before you can get to the clutches/steels/ramps/spider and side gears. You'll find (IIRC 4) phillips headed screws under the ring gear, and it will all be clear once the ring gear is out of the way.

I have some images at home of this LSD -- somewhere on my PC upstairs - I will look for them tonight.

Paul902

OK, next step is removal of the ring gear. I was hesitant to get further into this if I needed to pull off, (and press back on) the carrier bearings, since I would need to get a puller, and find a shop to press the bearings on in the final step. Since it is possible to service with the bearings in place it makes it much more straight-forward for an at-home DIY.

The ends of the 3 screws located under the ring gear are visible on the top of the piece the ring gear is bolted to. You can just make them out at 10, 2, and 6 O-clock in the second picture I posted.

I also saw the open diff in the WSM, but not the LSD. I was unsure where the clutches and steels were located inside it and therefore if I could access them without removal of the bearings.

Garth, I'm not sure what you mean by "cones" and "cups". Is this the bearing "races"? I would assume that if the bearings were to come off they must be put back on the same side so that they mate with the correct race.
I'll post some more pics when I get it apart.