Ok, Im in a bit of a bind. I'm installing my new clutch tomorrow and I bought 3 quarts of Mobil 75w-90 fully synthetic fluid for it. BTW its GL-5 rated. I need to know if this is safe to run in the car. The owners manual says to use GL-4, but I'm not sure if it makes a difference. Any recommendations?

Also, what would you guys recommend for the transfer case. Thanks in advance.

JC

 

Don't put that stuff in your tranny. GL-5 will eat the yellow metal used in the synchronization gears. Plus, you will get locked out of almost every gear. I know because I made the mistake of putting it in my main tranny, but only for a couple days. Then I had them put normal GL-4 fluid in the tranny.

However, that stuff (Mobil 1 75W90) is in my center & rear diffs, with the $5 bottle of friction modifier in the rear, and it seems to be working fine. If you can afford it, I would put the DiaQueen LSD fluid in the diffs, and normal GL-4 in the main tranny (although there have been mixed results with redline and synchromesh, some good some bad).

 

Don't use it. Go to Autozone and buy Pennzoil Syncromesh or go to a GM dealer and buy their Syncromesh. Pennzoil is half the price, but the dealer always keeps stock unlike the auto parts store.

 

Good info fellas. Ill try the syncro mesh from Autozone.

Thanks!

 

BTW, the Mobil 1 you bought can be used in the other diffs. I am running that in my TC.

 

Thats good to know. I was gonna return it in the morning. I guess I'll keep a quart of it then. Thanks for all the help.
Im trying to get all this last minute info for my clutch install in the morning and its been a PITA working out all the details. I hoping to have it all done in 5-7 hours. Ill let you know tommorrow night how it all turns out.

JC

 

I used the NISSAN 75W-85W GL-4 and it shifts great. this stuff probably Castrol syntorq LT. a special non-polymer full synthetic formula. I cant get Nissan or Castrol to admit it. This is what the 350z uses. seems the all the companys are using the 75W-85W for better cold shifting.

 

how about redline mt90 in the tranny. Would this be a good oil to put in?? piece.........

 

I ended up getting the pennzoil syncromesh. It didnt have any weight ratings on it so I hope its the right stuff. Anyway I guess I'll know tomorrow. Didnt get done with the tranny today. Got the tranny off and the clutch mounted up and thats it. Definitly alot of work and not for the faint of heart. No real problems though, inner axel splins came out no problem and the transfer case pratically fell right out. Even the tranny came off without much effort.
Its really not a difficult job, just alot of stuff to remove. SHould be finished tomorrow in a couple hours. I think if I did another one it would take much less time. Maybe I'll go in to the clutch buisness. Anyway, thanks for the advice on the tranny fluid and I'll report back tomorrow how it turned out. later.

 

Yes, MT-90 in the Transmission/transaxle (same thing).

Royal Purple SAE90 in the Transfer case and also the rear diff.