This is a 08 Sahara with 55k miles and it is time for some "maintenance"...

Pulled Rockhard winch bumper for scrapping and painting (powder coat didn't do so well), air filter swapped (wix made in Vietnam), plugs and wires due in from Rock Auto, diffs got fresh 80w-90, transmission was left alone since dealer rebuilt 10K miles ago, and T-case is last...

The book says ATF4+, but why? Is ATF3 or dextron 2 sufficient? what about 10w non-detergent motor oil? or even tractor hydraulic fluid...I would think that tractor hydraulic fluid would work just as well for that type of speeds and lubrication.

Every other four wheel drive we have uses regular gear oil, or even GL-1 straight 90 gear oil in the T-case. (the military power wag speck is MT1 or GL1.)

I stock two grades of gear lube, three grades of motor oil (20w-50 motorcycle, 15w-40 rotella and 5w-30 mobil one), two type of tube grease, tractor hydraulic oil and ATF for the 68 dodge d100 318/727 with headers, holley, highrise and glasspacks, but NO ATF4+

Do I need to add another bucket of oil type product to inventory?

or I could switch the ATF4+, I saw NAPA stocking the five gallon pails at a good price.

Howard

 

Why so resistant to ATF+4 in your transfercase? Your dealer used ATF+4 in your trans. You used gear oil in the diffs. I would think you use motor oil in the engine?

Guess I'm not understanding your post.

Transfercase uses 2 qts ATF+4.

Trans, T-case and PS all use ATF+4.

 

My question really is WHY ATF4+?

Historically T-cases and manual transmissions use gear oil, and ATF has less drag (friction) than gear oil for improved fuel economy, but why choose ATF over the 10 SAE hydraulic fluid used in heavy equipment and tractors?

As a degreed mechanical engineer, I often ask these design based questions...

Howard

 

I know my 2000 TJ called for ATF. 1991 YJ I think called for gear oil in the same np231. So I'm guessing they changed it in the 90s.

Mileage is probably a strong reason for this.

 

I thought it was kinda weird to. I use sycromax from royal purple. It is gear oil designed for manual trans and transfer cases that call for the use of auto fluids. I think I read that the ATF is less corrosive and that's why it's used ( don't know ) but that comes to mind for some reason...

 

Do you use the synchromax in your manual tranny also? I just bought some.....going to do mine next weekend......hopefully.

 

Now, what exactly is synchromax? I suspect it is conventional hydraulic oil with an addititive package...sold by the quart at gallon prices. Last time I looked, a five gallon bucket of tractor spec hydraulic fuild was $35, while synchomax is $15/qt.

 

I do. I did them at the sametime it shifts smother now. my cousin has a 05 rubi 6 spd I got him to switch because he was having 3rd gear noise and he said that it made it better and the tranny smother but only after he did the transfer too. I have royal in my engine, tranny & transfer and tomorrow I will have purple in both diffs

 

Synchromax is about 19 it is unique to royal purple and is for manual trans and transfer cases to specifically call for ATF

 

Use it for the manual Trans only transfer case takes automatic Trans fluid