I want to change all my lubricants to synthetic. The engine has been running it since about 50k. I will be putting it in the diffs this week. I want to use ATF +4 in the tranny, but the information is conflicting. The manual says that 2000 and earlier use ATF +3, but I've read here and elsewhere that you can move up from +3 to +4, but not the other way around. Is this true? The transfer case calls for Dexron III, but will it take the +4, as well? Is the viscosity of the Dexron and the +4 about the same? Thanks.

 

+ 4 Is what you would use. Amsoil and Royal Purple both make one that is compatible. Whatever you put in the transmission put in your transfer case as well just in case you develope a leak in the seal. I also run Royal Purple gear oil in both diffs and has had zero issues.

 

There was a TSB in 2001-ish (when ATF+4 came out) that stated that all Chrysler vehicles that were recommended to use ATF+, ATF+2, and ATF+3 were now to use ATF+4. None of the fluids above are sold anymore.
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Does that go for the transfer case? Dexron III is still available and that's what my manual calls for. I'd prefer to run the same thing in both the tranny and t-case.

 

Yes. Use ATF+4 in T-case for the reason in post #2.
You can use the cheap stuff like Advance Auto parts brand, Coastal, or Supertech.
It is all the same thing, just cheaper.

BTW when putting the fluid in the T-case, use the squeeze cap that comes on gear oil bottles. Makes the job a whole lot eaiser. Also put a drain plug in the tranny pan.

 

Amoils oil here front and rear diff t-case and tranny. No problems here. I think they need to be changed its been a yr now. With a lot of hard wheelin. Not the motor. That will be fixed soon.

 

t-case drain plug takes a 10mm allen, 3/8ths fits but its loose. thought i'd throw that out there since its not a common size. also i found out the other day that if you get a leak between the tranny and the t-case that your transmission will be a quart or 2 low and the vent hose on the passenger wheel well in the engine will be leaking transmission fluid because thats the overflow on the t-case.

 

what exactly is name of the royal purple type that is equivelant or better than atf 4, i would like to change my t mission and tsfer case fluids and like 2 above says they should match

 

i don't know about the royal purple, i have valvoline atf4 in my trans/t-case now.
post #7 is a lie too. i was reading what someone else put up. i had those seals go a little while back and my transmission was a little low along with the transfer case shooting a quart or two of fluid all over me when i went to check the level but the vent hose wasn't leaking. so i guess it was a partial lie.

 

Royal Purple does not make a fluid that meets ALL the specs of ATF+4. Suprisingly, ATF+4 is more common than Royal Purple and is cheaper, so why would you want to use the latter?