U4EEAH

I have had multible failures of my 993 gearbox (close ratio, lsd, Peter Dawes). Any advise on the best oil?

LVDell

Mobil Delvac. I buy mine from Lufteknic.

M758

I used Redline heavyshoof proof in my 944 spec gearbox and 944 Turbo S street car gearbox. I asked Chris Cervelli about gearbox oil and he gave me the redline stuff. I believe this is stuff he ran in 993 RSCS cars.

LVDell

More info (from the Delvac write-up):
Original fill in 996/997 GT3/Cup cars, and GT3Rs. Works well in all 901, 915, G50, G96 gearboxes. Used extensively in Porsche Motorsport products in every grueling test there can be LeMans, Sebring, Daytona, etc. We also use it in our service department in all street and race cars. Works in cars with or without (LSD) limited slip differentials.

http://www.lufteknic.com/Merchant2/m...ode=lubricants

DanR

how often do you guys change the gearbox fluid on your track cars??

LVDell

After every season (spring, summer, fall).

Gary R.

With a 915 you just have the rebuild shop drain it, that usually equates to once a season... if your lucky.

DanR

oh Gary, you are on form today!!!!! That said, the spanners on my car NEVER seem to go cold so I may have to start listening to you a little more!


PS typo - you meant 951

Gary R.

See, you immediately assumed I was taking a shot at 944's and 951's but in reality I am talking about the 915 gearbox in 911's from early 70's up through 1986! Most of us use Swepco BTW..

Though the 951 statement would be right up my alley wouldn't it..

chris walrod

Could you tell us more about the kind of failures? What oil used? Oil change frequency? Any images of these failed parts?

M758

Every couple years. Ahh the joys of 135 ft-lbs of torque.

bgiere

Something is missing in the equation...what type of motor is connected to the gearbox? Strange to have gearbox failure (I assume?) unless you are grossly overloading it or it's not being rebuilt correctly. For lube, use the Mobil Delvac or Redline 75w90 NS. When I did mine I asked Brian Copans and he said both lubes are excellent. I change mine 2 times per season and send it in to a lab for analysis.

DrJupeman

Fwiw, I usually change mine about 2x/season (20-24 days) with the Mobil Delvac.

LVDell

To echo what Brant said, when Copans rebuilt my gearbox he said he would ONLY stand behind his work if Delvac was used.