i think it's time i replaced my fluids in my truck for the sandy/dry/hot season. so i want to know what is the BEST oil to use in high heat but for best performance of the parts.

whats the best all round fluid for the following parts:
Transfer Case
Front/Rear Diff.
5 speed manual Transmission

I all ready changed the engine oil.

 

depends on the temperatures...plenty of oil viscosity threads

 

You do realize you're going to get a lot of opinions on this, don't you?....lol

I don't believe there's a "best" one out there. There are just several good ones to choose from. I always go with synthetics (as a lot of people do and like to debate over) and that would include Mobil 1, Amsoil, Redline, and have on occasion used some "off" or less well known brands. I really liked Amsoil, but it had become inconvenient to get.....too many hoops to jump through. Mobil 1 I believe is fine, but I found my transmission to be happiest with Redline's MT-90 ...... GL-4, more specifically. Roger Brown (4crawler) has a write up on his web site talking about Redline products (in the diff's, t-case, and transmission) that inspired me to use it. That, and the several threads about MT-90 itself. Currently, I have Mobile 1 in all but the tranny. Next lube change I'm going with Redline, though. I've just been really impressed with how my tranny has responded.

I don't live in or ever go in hot, sandy conditions, but I can tell you from the heat of heavy hauling and towing (plus living in a hilly region...and Arkansas can get rather hot during summer) synthetics have made a difference. They don't break down as fast, transfer heat better, and coat the gears and what not better.

Oh, and if this is any kind of testimony, my 22re recently experienced a valve/piston collision. The timing chain jumped time. I had the head rebuilt and when my old pistons were returned to me there hardly any noticeable wear on the valve stems.....which is not often the case with 220k miles. Plus, the cam, bearing caps, and journals were still well within original specs. I've been using synthetics in the motor (more often than not.....due to certain circumstance) for as long as I've owned the vehicle. For atleast 100k miles.

 

 

Right, Alex....

There's that to consider, also. Not just brand or type (dino vs. synthetic), but also viscosity. Generally, for hotter climates heavier weights are recommended, but that applies mostly to the motor and whether it will see alot of higher RPM's and heavy loading.

For what I'm guessing as to your application, sticking with factory recommendations will be quite adequate.

 

i use redline in my bmw
and when i bought my 4x, i just replaced all fluids from the dealer (coolant especially).

greased the driveline too.