Trans, Diff and Transfercase??

[Johnny]

Capacity has a lot to do with it, but a lighter fluid whatever the capacity will run cooler under normal conditions.

Here is a simple test kind of to the extremes. Take a pot of water and a pot of cooking oil and place them on the stove. Heat them up at the same time at the same temp, turn off the stove and see which one cools down the fastest. Motor oil and gear work the same way, only not to the extreme as water and cooking oil.

 

[Bror Jace]

For any transfer case calling for an ATF, why not run RP Syncromax? It's synthetic, is as thin as ATF and has an additive package more appropriate for a box full of gears?

 

[Johnny]

A lot of folk do, or something equivalent to the RP product you speak.

I would not just because the manufacture does not recommend it. First I want to know what the manufacture recommends, then I decide what brand of product I want to use that meets that recommendation.

 

[zrxkawboy]

Originally Posted By: RageOfFury

Dexron in the T-case? big no no. ATF+4 only!


I disagree. Though ATF+4 is fine in the case, so is most any other ATF. I run a synthetic Dex in mine, just because I have extra on hand. The case doesn't care if it's fluid has friction modifiers in it...your transmission does.

 

[zrxkawboy]

Originally Posted By: RageOfFury
I checked with some Jeep gurus on another forum and they approved of this.


The guys on kj forum may be knowledgeable about mechanical matters, but like most other automotive forums, very few have knowledge of lubes. Look at tjkj, for example. He may be an accomplished mechanic, but some of his statements about oil are downright ludicrous. Things like: "don't use an oil with moly in a tight-clearance engine like the 3.7, the moly particles are too large and will cause damage". When I called him on it and asked him to back it up with evidence, he responded with his usual arrogant, irrelevant insults. I'd stick with this forum for oil and lube advice.

 

[unDummy]

I'd use ATF+4 over any mineral or blend DexronIII.

Use either ATF+4 or any full synthetic Dexron-III.

Cost/availability of ATF+4 is why I would use it!

I recommend upgrades over what the OE wants to use. When I worked for those 'manufacturers', what was recommended was based on what was being used already, what was cheapest, and what was acceptable. They rarely recommend the best.

 

[Johnny]

unDummy, which manufactures do you speak of? Surely not folks like Dana, Spicer, Eaton, Rockwell, etc.

 

[FFeng7]

Thanks guys. I think what Im gonna do is ATF+4 in the Trans and Transfercase. I think I going with the 90w140 syn in the rear. most likey Mobil 1. I will not be doing any heavy towing but I do drive on the beach alot. I think that driving on the beach put a extremly heavy load on the drivetrain. Thats why I think the heavier lube may be better. Still I may stay with a 75w90 in the front. Just because it is used less. Thanks and I will let you guys know what I do.

 

[Johnny]

If you're going to purchase from a parts store, be sure and tell the you want 75W-140. No such thing as 90w140 and you really might confuse them. The Mobil 1 gear oil is a very good product.

 

[Zaedock]

Originally Posted By: FFeng7
Thanks guys. I think what Im gonna do is ATF+4 in the Trans and Transfercase. I think I going with the 90w140 syn in the rear. most likey Mobil 1. I will not be doing any heavy towing but I do drive on the beach alot. I think that driving on the beach put a extremly heavy load on the drivetrain. Thats why I think the heavier lube may be better. Still I may stay with a 75w90 in the front. Just because it is used less. Thanks and I will let you guys know what I do.



Sounds good. The Mobil 1 75W140 is a nice gear lube - although I still think it's overkill. Driving on the beach is no strain on your rear axle.

What ever you choose, good luck and Happy Trails

 

[gomes512]

I to think the 140 is overkill. I came to the realization when the 75w-90 I've drained the past 2 times held up fine. Both front and rear axle magnets have nothing more than a fine fuzz after 30k. I occasionally tow a 1 ton and wheel the heep a bunch in the summer.

As for tcase, I've used atf+4, dex3 and syn 5w30. All three have worked fine for me in 30k intervals.

 

[unDummy]

Yes Johnny, and I do mean those manufacturers and many automakers, motorcycle manufacturers, along with custom gears for low volume gearboxes(industrial, custom, motorcycle)....

140wt is NOT overkill. Its usually a good bandaid for weak or hot diff. With the massive MPG movement, why would ANY manufacturer even recommend 140wt? Hint hint check the metal recycling bin at your local auto dealer!!!

Lucky for the thread starter, the 3.9L shouldn't stress the rest of the drive train much.