dont some work on my car,, wondering what is every one using in there standard 833 4 speed box ??? 80/90 weight 140 weight ?? whats woring better,,,any one have a comparasin ??
I used to run straight 90w in my 4 speeds. For the Sedan (assuming I put a stick in it) I'll probably go all synthetic. And for the record, Chrysler used to recommend ATF in a 4 speed in "cold weather climates". DON'T do that where it's not gonna get below freezing.
I put in some kind of gear oil the first time I filled a tranny, But I find that all the 4 speed and manual 3 speeds that I have taken out, have ATF in them. So that is what I put in my 4 spd this time. Don't know about the cold climate part of it, I have had a 4 speed for years, and they always seem fine hot or cold.
An MTL 75w-90 GL4 is good for heavy duty/hot operation. The newer GL5 hypoid gear oils in those lighter weights are probably OK, but make sure is a dual-rated GL4/5 rated fluid that is not going to eat the synchros. I'd stay away from anything 140 - too heavy. You won't notice it with the FMs in a synthetic variety, but just not needed - overkill.
ATF was the factory fill before modern synchromesh fluids came on the scene. Those are the best choices for all around use nowadays.