Originally Posted by pwdrhound

I changed my gearbox fluid 5x this year. I do it every 6 track days using Mobil1 Delvac 75w90. The stuff comes out pretty filthy especially if you have an LSD because of all the particulates that shed off the clutches. Delvac is standard fill in the Cup cars / GT2/3 which all of which use an LSD. I buy Delvac in 5 gallon pails at $150 which works out to $30 per change since you need 1 gallon. For a stock 996TT with an open diff the OEM Mobilube PTX or Shell Transaxle work well as they are slightly thinner than the Delvac and will flow a touch better in freezing temps. You can get the Shell from your dealer in 1Liter bottles for about $25 each. Most gearbox builders will tell you to change at 15K mile intervals for street driven cars.

Originally Posted by evil 996tt

I just changed my stock fluid out to the Mobil 1 Delvac 75w90. When the tranny is cold, grabbing 1st gear is pretty hard to do. After 10-15min of driving it is easier and throughout my 1hr commute, it shifts very nicely.


Is this normal for the Delvac?

Originally Posted by evil 996tt

I just changed my stock fluid out to the Mobil 1 Delvac 75w90. When the tranny is cold, grabbing 1st gear is pretty hard to do. After 10-15min of driving it is easier and throughout my 1hr commute, it shifts very nicely.


Is this normal for the Delvac?

Originally Posted by JSBear

No issues that I can think of, including 1st gear when cold.