use redline mt-90 in 1275 rear differential?

[recordsj]

any problem in using redline mt-90 in a 1275 rear differential?

 

[ChrisS]

I'd contact redline. Their MT line is for manual transmissions and MT-90 is similar to 20w-50 from a viscosity standpoint. I thick they can recommend one of their gear oils though. Beware that you will most likely notice an increase in the leaks with a synthetic oil, especially at the hubs.

 

[recordsj]

has anyone used this oil in the 1275 rear differential?

 

[Hap Waldrop]

I think Chris nailed it, maybe a tad on the thin side for a diff, not to say it won't work fine, Red Line does NOT recommend it to be used for rear ends, right on the bottle it reads:

This product was not designed for rear drive differential use which requires a GL-5 lubricant.

Thats was always enough information for me to not ever put it in a rear end. They recommend using their SAE 75W90 API GL+5 Hypoid gear oil for diffs, you should have bought cheap 75/90 gear oil, save some bucks, and for sure been right.

In short, if it were me,and based on what Red Line prints clearly on the bottle, I'd drain it and put the right stuff in it.