Best oil for manual transmission

[SPR]

Hey Loren can you please check the rennlist discussion on the tranny fluid as there seems to be some uncertainty regarding the amount, i.e. whether to fill it until it comes out of the fill hole- which is always more than the diy states or to simply put the diy amount in and call it a day. Thanks Sean I am going to change mine again and exchange whatever the hell I have for the correct stuff from that dealership. Maybe I should have them check my tranny beforehand etc.? Any suggestions? Again, I am worried they did sell me the wrong stuff and some damage might have occured?

[1999Porsche911]

Hey Loren can you please check the rennlist discussion on the tranny fluid as there seems to be some uncertainty regarding the amount, i.e. whether to fill it until it comes out of the fill hole- which is always more than the diy states or to simply put the diy amount in and call it a day. Thanks Sean I am going to change mine again and exchange whatever the hell I have for the correct stuff from that dealership. Maybe I should have them check my tranny beforehand etc.? Any suggestions? Again, I am worried they did sell me the wrong stuff and some damage might have occured?

The purpose of the location of the fill hole is to insure that the correct amount of lube is put in the tranny, and NO MORE. Whether it will take 2.5 liters or 3 liters, IF the car is level, ALWAYS fill it to the bottom of the fill hole. If you want to be sure or the car being level, jack it up and remove the fill plug. Insert your finger and make sure the lube is right at the bottom of the hole. WORSE than putting too little lube in, is putting too much. The fill hole is positioned so you cannot overfill on a level car.

Edited March 9, 2006 by 1999Porsche911

[teeerex]

Having done this myself on a C4 (front and rear, with plenty of posts on it btw) - a lot depends on how level the car is - only a few degrees out will mean a 'lot' is left in the transmission. I actually measured the amount I got out to see if it was as expected and raised the front of the car some more as it was less that I though, and low and behold - got another 200ml out this way. Then I only put back in exactly the same quantity that I got out + 50ml or so. If I recall it was just below the filler plug level wise. The front tranny being smaller, didn't seem to be that fussy on drain angle.

Just out of interest P1999, why would overfilling by a small amount be bad ?

Richard.

[1999Porsche911]

Having done this myself on a C4 (front and rear, with plenty of posts on it btw) - a lot depends on how level the car is - only a few degrees out will mean a 'lot' is left in the transmission. I actually measured the amount I got out to see if it was as expected and raised the front of the car some more as it was less that I though, and low and behold - got another 200ml out this way. Then I only put back in exactly the same quantity that I got out + 50ml or so. If I recall it was just below the filler plug level wise. The front tranny being smaller, didn't seem to be that fussy on drain angle.

Just out of interest P1999, why would overfilling by a small amount be bad ?

Richard.

Like the oil level in the engine; if you have to much oil, it can start to get airated which is not good. It also puts additional drag on the gear rotation.

[Phokaioglaukos]

Over on Rennlist there is a thread HERE that addresses the lightweight flywheel change but also what manual transmission fluid/gear oil to use. There is some continuing confusion. One poster says that Mobil 1 SHC 75W-90 is the latest flavor of the month (PMNA recommended : part #999.917.062.00), but Mobil says that product is now discontinued.

Any thoughts from here would be much appreciated.