Well after my successful front differential refresh with new bearings, I finally had a chance to take the car out for a spin today.

We'll the good news is, the car is quieter, but the bad news is, now I can pinpoint the off throttle/coasting noise coming from the rear.

So, on the lift the car went at my buddies shop today and after extensive probing with a stethoscope we've tracked it to the rear axle final drive

Anyone have any experience with differential repair on porsches?

Does the engine have to come out?

Is it gonna be fun if I decide to do DIY?

 

You are very handy, so I'm sure you'll be able to drop the tranny. Pelicanparts sells a brace that holds the rear of the motor up in place once the transaxle is removed, and allows the car to remain mobile so it can be rolled around. The tool is $300, but I suspect one could be fabricated if you weld.

Here's the issue... "while you're in there" you should really check the condition of the synchros and bearings in the tranny. The 4-plane bearing goes on these trannys and causes shifting issues that also wear other components as the bearings wear.

Other things to consider:

Clutch wear/condition... You might find you need a new clutch and pressureplate, and at a minimum I'd put in a new release bearing.

Clutch Hydraulics... Enough information out there on the garbage Porsche saddled us with in regards to the clutch hydraulic component failures out there... Now would be the perfect time to swap to the GT2 based setup.

Unfortunately anytime you drop the transaxle, it is gonna cost you more than you expected.
Mike

 

That's an idea Dang I was looking for an excuse to get a lift and to mess with the intake tubing to chase all leaks. Anyway it's a TIP so no clutch.

 

If I was you, I'd be hoping this was an opportunity to put in a guards 60/40 LSD.

 

My lift is the best tool I've ever spent money on. It's been a life and money saver time and again.

Since you have a tip, you don't need to worry about that whole clutch/hydraulics issue. You might look into a different torque converter, or as mentioned above, an LSD of some type...

Mike

 

You can pull the diff w/ the eng & trans in place.Its a little tight,but once you drop the motor down a bit it gets a bit easier.A lift is a must for this job as the right rear suspension must be removed to access the the diff cover.Not sure if anyone offers a perf. diff. I was unsuccessful in finding one for my car & went back w/ stock.the porsche parts catalog is pretty useless for looking up parts on this mercedes trans. & I ended up sourcing my diff bearings at a local bearing shop

 

Were you able to look up anything in the mercedes catalog? Which bearings did you change?

 

Did not have to use the Merc catalog.Pricing proved to be a little too high for the items I needed,so I sourced a salvage trans & removed the required diff carrier.I replaced the carrier bearings when swapping,everything else ck'ed out.Had to go in there due to a bad inner cv joint which scored the stub axle drive flange & diff carrier.

 

So I understand it was the passanger side you were having the main issue with. Did you pull both axles when removing the carrier?

How much can you lower the engine safety without binding up any lines and disconnecting everything? I was hoping on not having to tear the suspension apart since I don't want to do an allignment, but it looks like I might have to.


I'm still planning out on how to go about this, I found this thread in the GT forums which is giving me some ideas and courage to do one of those DIY writeups It does seem to be easier on a GT3 thou.

https://www.6speedonline.com/forums/...sd-buster.html

I drained the differencial oil today and it looks like brown sticky sludge. When you shine a light on it it looks like brown metallic paint which cannot be good. I'd recommend to everyone to change it more often than 60,000 miles.

 

The link diy is similar,but w/ the tip the diff side cover is on the right side & there is no room to remove it w/ the r rear suspension sub frame inplace.You only have to remove the r driveshaft & I dropped the motor about an 1 1/12".I did leave the emer. brake cable attached & supported the rear subframe w/ a trans jack during repair.The job looks intimidating at first,but the rear subframe is not that hard to remove-3 large studs to body,a cross brace & center suspension brace w/ 4 bolts-upper 2 stay in place since the center brace top holes are open end.You will need an aligment after ward & I'am a little sceptical about not ck"ing ring gear preload as in the diy.I did this by feel,but I have alot of exp. w/ drivetrains-you should be ok if just changing carr. bearings-anymore than that get it done by a proffessional-a mistake in clearances will result in a very expensive repair

 

In the GT3 DIY i posted looks like he was just changing clutch packs and there fore none of the other outside measurments changed and no bearings were replaced. I definatelly plan on doing it the right way and checking runout and backlash and inspecting for play.

BTW. How did you get the subframe around the intake ducts? Do these come out?

 

doublepost

 

To give you guys an update.

I tear into it today. Just like sweeney186 said, it's a piece of cake. I was able to remove the axle and all the suspension parts in pretty much one piece minus the braces.

When I dropped the engine down after removing the brace and crossmember I was shocked as to how far you can lower it and how much access you can get to the top of it. I know before I put it all together I'll be troubleshooting all the intake leaks

Well the good news is it's not the rear differential I'll post pics to prove that I took it apart.

But...there is always the but......if it's not the differential bearings than WTF is it?

So, I gotta tear more stuff apart to track it down which makes me not happy.

 

maybe rear wheel bearings?

 

They are super quiet when you put a stetoscope to them and the noise doesn't change when turning.

Next thing I'm gonna look at tommorow is the bearing that supports the stub shaft that attaches to the driver side axle. If that's not it than the front of the TIP that splits the output shaft is comming apart as the noise is even there when coasting in neutral.