Manual transmission oil question

[Moisesa4]

Here's a dumb one, I purchased Red Line 57904 (75W90) Synthetic Gear Oil, not MT-90, I don't think they are the same. Is it bad for the car? I don't mind returning it and waiting a few more days for the right stuff but if it's ok I'll keep it. Any advice?

[B6JoeS4]

Not sure if it really matters but the stuff you got is gear oil for differentials and stuff. It's GL-5 rated. MT-90 is GL-4.

Is this for the trans or the rear diff?

dparm should chime in soon. he will know

[Mr. Corey]

I think theirs a thread kicking around with all the gear oil specs.... might be able to give you an answer on if you can use that for both.

[Moisesa4]

It was intended for the transmission, but if it's good for the diff that's great too. Thanks for the help.

[Moisesa4]

I read the thread and MT-90 is listed as good, the one I purchased isn't on the list but it has the right weight and viscosity, I guess when it arrives in the mail I'll find out the GL rating. I think thats what's gonna mess me up.

[B6JoeS4]

Hold the phone! We haven't figured out if the stuff you got is suitable for the trans.

[Moisesa4]

Holding. Don't actually even have it yet, should be delivered tomorrow.

[B6JoeS4]

The stuff you ordered is GL-5 so you CANNOT use it

Escerpt from dparm's thread:

Due to its size, the transmission requires 3.5 quarts of GL-4 75w90 fluid for a change. The key piece of information here is GL-4. You cannot, I repeat CANNOT use a GL-5 fluid.

Why is GL-5 bad news for us? It has to do with the additive packages. GL-5 is not simply the “new version” of GL-4. It is a different specification all together. GL-5 is not necessarily better, it’s simply a spec for different usage.

GL-4 fluids contain about 40-60% as much additive as a GL-5 would. These additive packages can be corrosive to certain metals. While the transmission would function with GL-5 inside, it would wear itself out very quickly. Some cars can run GL-4 or GL-5, ours cannot.

[dparm]

Here's a dumb one, I purchased Red Line 57904 (75W90) Synthetic Gear Oil, not MT-90, I don't think they are the same. Is it bad for the car? I don't mind returning it and waiting a few more days for the right stuff but if it's ok I'll keep it. Any advice?

You can use the 57904 for the rear differential. You cannot use it in the manual transmission.

[Mr. Corey]

Here's Dparms thread with all you need to know about trannys!!!!!!! http://www.audizine.com/forum/showth...n-Fluid-Basics

[Amsterdamned]

You can use the 57904 for the rear differential. You cannot use it in the manual transmission.

How does the Redline 57904 compare to other 75W90 Syn. Gear oils? This is actually what I'm running now in the rear diff. I have Motul in the tranny but couldn't find the Motul gear oil for the rear diff and ended up going with the redline.

[dparm]

You can use the same Motul Gear 300 fluid in both. It is dual-rated GL4 & GL5.

The Redline stuff is fine for almost anyone, though I still prefer Gear 300 because of the high viscosity index.

[Moisesa4]

Alright thanks. I'm going to just return it and go with Motul all around. Tranny and diff. I guess I had an itchy trigger finger on amazon and ordered the redline before I even checked to see if it was compatable with our cars. thanks for the help guys.