Help! New Wrench says there could be a problem with differential -
 

The former mechanic shop that I used to service my 1983 944 closed down, so I am trying out a new wrench for a state inspection and oil change as of this morning. The shop seems reputable and works on Porsche, Ferrari, Audi and Benz - a step up from my former mechanic - he seems knowledgeable and honest. He just called, however, and said that while he was taking a test drive he heard a loud high pitched noise from the rear, which I honestly had not noticed myself. I haven't been driving the car regularly due to the weather and I just installed a new set of rear speakers so I have had them turned up when driving. I am trying to figure out if he is trying to take me or not. I have read other posts, but:

What type of noise would the differential in need of repair make?

What would be some of the other symptons?

In other posts, it has been suggested that a differential may be repaired by the bakc-yard mechanic - so how much should this cost?

Thanks alot -

Jeremy
1983 944

My 951 has been whining for several years in 2nd and 3rd. It's going to keep whining until it breaks. Then I'll have it rebuilt.

I have a wind in first gear with my newer tranny, but I don't even worry about it. Mine is just my R&P being pissy. Find out if yours makes the sound in one gear or every gear. I wouldn't worry about it unless it does it in everygear.

BTW-My old tranny made a weird sound on decell. But that was with the crack R&P, cracked spider gear, and a broken carrier; basically a BIG oops on my part.

Some whining is considered normal - a good gear oil can help.

Excessive whining and or groaning could be bearings.

I would bute the bullet and get some Swepco (avail here at pelican) It is really good stuff - a little pricy, but very good. Drain tranny - observe what comes out - some silvery dust is normal, chunks are bad.

refill with the good stuff and re-evaluate

AFJuvat

I bit the bullet and put Mobil 1 in my tranny a couple of weeks ago. The 1 to 2 shift is smoother now.

I went with AF's advise and used swepco. The trany got alot quieter. I am not sure but I have heard that whining is caused by a cracked ring gear. Mine whines in first at low spead I am not worried about it.

Rear torque tube bearing? This car is 20 years old.