Chevy conversion question

[kroy1968]

New owner here. My jeep has the 4.3 chevy conversion with the 700 R4 transmission. I need to do fluid maintenance all around. I know the transmission requires Dexron and the transfer case calls for ATF 3 or 4 but I've read that I can use the Dexron in the transfer case... that sound right?
Also, is Royal Purple really just that much greater. It would cost almost $75 more for Royal Purple (which does solve the above question because it covers all types) than synthetic valvoline.
Since you've read this far you must be interested in Fluids so I'll ask another question - 75w90 ok for both differentials

 

[Steel City 06]

75W90 is fine for the differentials. I run 75W140, but that's because I run my car harder than most. If you live somewhere hot, or do a lot of freeway driving or towing, the heavier 75W140 might be the better choice. If you have a factory limited slip, make sure you get the Mopar LS additive.

 

[kroy1968]

I do live in GA and it is hot so maybe 75w140 is a better choice.

I'm still trying to figure out how to tell if I have factory limited slip axles