Whats transmission oil should I use for my F28?

[PrecisionBoost]

Castrol SMX is SAE 75W-85 and API GL1-4 compliant.

Some cobalt guys on another site were talking about changing fluid on their F35 gearbox which seems to be the same API GL1-4 as the F28 fluid.

Here are some equivalents (when using an "equivalent" you take risks of causing problems):
-Special 2105 Quaker State Mineral 75W/90 API GL 4EP
-Super Qudralube Quaker State Mineral 75W easy shifting API GL 5 EP
-High Performance Quaker State Mineral 80W-90 also to differential LS-EP. API GL 5
-High Performance Quaker State Mineral 85W-140 also to differential LS-EP API GL 5
-Synchron Fully Synt. Quaker State Helsyntet 75W-90 also to differential LS-EP API GL 5
-SMX-S Castrol gearboxoil fully syntetic 75W/85 API GL 1-4
-EP 80 Castrol gearboxoil Mineral 80W API GL 4
-Syntrax Universal Castrol gearboxoil semisyntetic 75W/90 API GL 4/5 LS

Ok... so Saturn and GM part number is 21018899 for the fluid in the F35.

I have to think that given the cross compatibility of the SMX-S between the F28/F35 and that the Cobalt guys were talking about how this special GM fluid was also used in Saab transmissions I think it's pretty likely that your best bet is the Saturn/GM fluid.

Oh.... one guy managed to find out that the GM stuff is also called "Castrol Synthetic BOT 0063"

So.... to me it's quite possible that the factory GM fluid is the SMX-S made by Castrol

It seems that the 21018899 fluid is common to almost every single Getrag/GM gearbox at this point.... I found that part number attached to dozens of different cars using Getrag gearboxes.

Me... myself.... I'm going to go with the 21018899

[exist3nce]

Wow thanks alot Chris! I'm going to head over to the dealer today and pick some up

[exist3nce]

I can't believe the dealer wants almost $30/L for that fluid...... what a ripoff. I found it on http://www.monsterpartsonline.com for $9/L hahah

[greenbluewoo]

could I use this for a d20 gearbox

[PrecisionBoost]

I think the D20 is just plain old gear oil..... but I don't think it will hurt anything to try it.

[greenbluewoo]

ok sounds good

[exist3nce]

So I went ahead and ordered a case of 6 of 21018899, from that site monsterpartsonline.com. It arrived today from UPS and I got killed on the duty

Anyhow, I drained my F28 and put this new stuff in, i think it feels a bit nicer and quieter. This stuff seems almost if not identical to the other fluid 93165290 which came in the grey bottles. The smell, colour and consistency all appear the same.

Heres some pictures of what the bottles look like.



On the back it says "...meets Opel's requirements for use in the manual transmissions of all FWD and RWD passenger cars worldwide."

and in the bottom corner... "OPEL B0400063"

[PrecisionBoost]

Good to know.... I will definitely be picking some up