Getting ready to swap out the old gear oil in my diffs,transfer case auto tanny. ... was curious what you guys would recommend, weight and product line.

It's a 94 4runner, with FJ60 axles... and ARB lockers (don't know if that makes a difference).

Would synchomesh be a good thing to add anywhere?

 

in the wrx world most people use redline gear oil. ive been using it for years and have nothing bad to say about it.

 

I run 80w-90 of the CHEAPEST oil I can find.

Oil is oil, if you're buying anything more then the run of the mill stuff you are WASTING your money.

Like posted above, if you have a nice sporty new WRX or STI like I use to drive then yes by all means run the good stuff. I was all Royal Purple in the STI. But these old trucks don't need it.

 

NAPA has this 75-80-90 stuff (that's what it says), their brand (so it's what, Valvoline?).....odd label (we joke that "hey, this is all the different types of gear oil in one!" around these parts). Everyone uses it, no complaints. Is there really much difference between 75W and 80W??

The fact that anyone's even CHANGING the oil in diffs, tranny and TC is a plus, LOL.....I just did mine at 183k, and I KNOW it was the original oil that I drained out.
(I could tell by the smell, ha ha).

 

Redline for all power train oils.

 

Redline & Amsoil are expensive but EXCELLENT lubricants. ONLY use GL-4 in the tranny or you'll end up ruining your syncronizers. Lighter weight synthetic protects better than heavier in most cases as it flows quicker when cold. Unless you are really putting it through the ringer with heavy towing, etc., heavy isn't necessary.