Confused on gear oil

I replaced all of the gear oil in my differentials, transfer case, transmission, and steering knuckles with the type recommended by the local drive train guru and parts supplier. He recommended 85W-140 for all except the steering knuckles and 80W-90 mixed with bearing grease for the knuckles. However, the factory service manual recommends SAE-90 or 80 for the transmission and transfer case and SAE-80 for the differentials. I couldn't find anything in the manual for the knuckles. Is the manual outdated or is the parts supplier confused? Also, is one brand of oil as good as another?

 

Manual was maybe written before the use of multi viscosity oils. 85-140 might be a bit stiff for us guys who get the colder weather but it should be fine for you in your climate. And the knuckle pudding is right as well, if you use just oil it will leak out and if you use just grease it will be too thick and not lube, so mixing the 2 is the trick.
Mike B

 

Im a bit confused when the term 'cold weather' is brought up. Is 'cold weather' a term given to the northen states? Im in central florida and it can get to the high 30s low 40s here in some winters. Should I account for 'cold weather' when choosing a lube?

 

80 / 90 weight oil in the diffs and trans, and 140 weight in the knuckles.

Gear oil in variable viscosity for the trans and diffs is OK, but I'd try to stick with the straight 140 for the knuckles.

140 weight oil is only a shade more viscous than grease, and if your knuckle seals are OK it should not leak out.

Don't overfill the knuckles. If you gotta stray from the exact measurement, err on the low side.

90 weight in the knuckles could leak out on to the brake shoes....

The jeep manuals for these models were written up to 71, and variable viscosity oil was in use long before that.

 

Just make sure you dont use GL-5 in the trans or T-Case.

 

Just wondering regarding the question asked on gear oil. Why not use the GL-5 type gear oil? Is there a difference in viscosity? Or will it harm the Trans - T-case?

 

Thanks sparky!

 

sorry about brining back old thread but novaks says gl5 is good.
i must be confused cause sparky says its bad.

"An 80W-90, API-GL5 or MT-1 rated fluid is very good." novak
http://www.novak-adapt.com/knowledge/t90.htm
on the bottom

 

i will just take back the oil i bought and get some non gl5 just to be safe.R)
oh well i was looking around and noticed this, and it only confused me more.

 

Nothing like confusing the hell out a folks, is there.

They got lawyers or politiciansR) or both writing their material now?

 

Count me as a resident in the State of Confusion.

I know my Troybuilt tiller says DO NOT use GL-5 because it will eat up bronze bearings etc. But generally no one seems to know or care about the issue.

Can anyone tell us seriously if this is a real problem or a theoretical one?

Pete