Help: What transmission fluid?
 

Good morning, so I found out (unfortunately while driving) that my adjustable bearings in my gearbox had disintegrated and got that fixed over the weekend so there is no more crunchy shifts. However it is still difficult to shift (and the clutch pedal is rather stiff). Especially into first. I'm thinking it could be the transmission fluid. What fluid do you recommend?

P.S. I have a C4

The spec in the manual calls for SAE 75W 90 GL5. I've been using Mobil Delvac 75W-90.

I'm using Swepco 201 but have used Mobil Devlac in the past. Both seem to work well.

Mobil Devlac in all 3 of my 911s with G50 derivatives.
Downside is a bit balky when cold.
Upside is excellent warm and hot performance.

Would delvac be ok for the c4 front diff too?

Yes

I don't see anything for Mobil delvac g50. Do you mean SAE 50?

I am sure he meant API GL-5

:cheers:

Typo.

Thanks for the advice!

Anyone uses Redline NS 75w-90?

I have the T shirt on C4 box rebuilds and my shift is like a knife through butter in all gears now so that's what they are like new/sorted. I'm using Swepco oil but I don't think the oil makes a lot of difference.

If it's not going into gear it could be worn bushes in the selection arms going to the box. It could also be very worn gearbox or engine mounts upsetting the selection geometry. Equally the clutch might not be releasing fully.

After that you are inside the box with any number of parts that could be worn. How many miles on the box so far?

To do any serious gearbox work you need to take out the engine and box. By doing that you would know how good the clutch is because it is exposed when the box and engine are separated.

Btw I have to ask what are the adjustable bearings in your gearbox? I've never heard of that

If you have an LSD make sure it has friction modifiers. Most do but not all yiou can add modifiers as well.

Would an 80W 90 be too much for a c2?

+1 Swepco 201 (80W-90) and a C4. Since switching to this a few years ago the gear selection just seemed smoother when hot..