Hi all,
I had a front differential on a C4S have a malfunction - ie. chunks of gear in the oil when drained. I had a indy Porsche shop put on a reconditioned front differential... all was well for maybe 200 miles .. and then it started whining .. i can hear it spin up with acceleration over 30mph and i feel like i hear it spin down as the car decelerates ( in neutural - no engine noise to compete )

maybe i am just listening for it .. could a torque tube or other issue be putting too much or too little stress on the front diff and causing this? I hate going back to the shop again but i dont think it is quite right yet.. and i dont want to destroy another front diff...

thoughts?

 

Hi Dave,

I must ask,...is there sufficient gear oil in the front differential?

If so, and presuming the correct oil was used, you may have a bearing or ring & pinion problem.

 

My first concern was the fluid used as well.

 

I would like nothing more to solve this with finding it is a gear oil issue. can you recommend what should be in the front differential and i will call the shop and ask specifically if this is what was used..

Thank you! What's the mechanism for buying you guys a beer if this is the solution??

 

I have Mobil1 LS 75W90 in mine. Seems to work fine. No beer required.

 

The front diff is not too sensitive on oil - just make sure its filled to the fill hole, and its a good quality 75W90. A whine is not usual so something is wrong for sure.

 

Run a search Mobil 1 DELVAC, its not cheap and you will not find it just anywhere. http://www.lufteknic.com/Merchant2/m...ode=lubricants