[njg2982]

It's been too long since i've done a proper fluid overhaul on my 2000 I6 4.0L with an AW4 and a NP231.

I've spent about an hour reading post going back and fourth on what fluids to use etc.etc.

This is my plan, so please let me know if anything is wrong/could cause issues.

AW4 - Royal Purple Max ATF (~5 qts)
NP231 - Royal Purple Max ATF (~2 qts)
D30 and C8.25 - Royal Purple Max-Gear 75W90 (~3 qts)

If you want to suggest an alternate brand please do so, i have just heard good things about Royal Purple.

Thanks!

[Texsun]

if you wanna continue paying that much for the rest of the jeeps life i would go Royal Purple all day!

[mickey85]

Royal Purple is good. Just keep anything Quaker State out of any orifice on any vehicle you own.

[Millermagic]

If you want something entertaining to do, go to a parts store and look up ATF specifications for the AW4 in other vehicles, you'll find that, at one point, it has had almost EVERY fluid specified for it - Mercon, Dexron, Toyota, Japanese, ATF+3/4.

I'm a believer that transmissions don't die from the wrong fluid, they die from being run 300,000 miles on the original fluid and being"shocked" with new fluid. An older unmaintained transmission is held together with deposits and ATF is a high detergent. I used Mercon V from Advance Auto last time. 10k miles later, it's still a transmission.

The transfer case does not care. It isn't using it to ttransfer power, it's using it for lubrication. Like a manual transmission. Cheap ATF should work.

[RMC_xj]

Originally Posted by mickey85

Just keep anything Quaker State out of any orifice on any vehicle you own.

Care to back that up? I've used Quaker State oil and Fram filters since I bought my Jeep almost 2 years ago.

[mickey85]

Originally Posted by RMC_xj

Care to back that up? I've used Quaker State oil and Fram filters since I bought my Jeep almost 2 years ago.

I once bought a '91 Pontiac Grand Prix that had Quaker State since new. It had a valve cover leak, so when I pulled off the VC, the entire inside of the motor was completely coated in black sludge - half tar, half crispy. There were no signs of overheating. Another car I had used QS oil. Same thing.

As for Fram filters - why would you do that to yourself? Two drag racing friends of mine though they could get by on a bit cheaper filter...the filter failed at 6000 RPM, crushed itself, and locked up the engines due to starvation. Same thing happened to me on a mostly stock AMC 258 I rebuilt - .030 over, 9:1 compression, stock manifolds. Sucked the filter, lost pressure and killed the new motor.


You're free to use whatever you want, but anecdotal evidence proves to me that it's not worth risking my motor for a few bucks. I'll stick with Wix filters and Mobil 1 or Valvoline.

[xjohio]

how often was the oil in that grand prix changed?

[njg2982]

Originally Posted by Texsun

if you wanna continue paying that much for the rest of the jeeps life i would go Royal Purple all day!

That's the only negative i've really heard about it. I may go Mobil1 too. We'll see, i hope to get it done soon.

[Wearingthin]

Autozone is doing the 5 quarts of mobil 1 and a filter for $30 right now, at least down here they are

[mickey85]

Originally Posted by xjohio

how often was the oil in that grand prix changed?

According to the notebook of maintenance/repairs the previous owner kept, every 5,000 miles after the first 20,000. Before that is anyone's guess, but as I picked it up with 90,000 miles, chances are good that the accumulation wasn't due to the first 20K...

[CJ7-Tim]

I use whatever Dexron-III/Mercon trans fluid that is on sale. The Cherokee Owners Manual and the Jeep Factory Service Manual both specify Dexron-III/Mercon for the AW-4. Regular fluid changes have a greater benefit than any super duper brand name fluids or synthetics like Royal Purple or Amsoil.

Originally Posted by Millermagic

....... transmissions don't die from the wrong fluid, they die from being run 300,000 miles on the original fluid and being"shocked" with new fluid. An older unmaintained transmission is held together with deposits and ATF is a high detergent.....

This is BS, piled high and stinky.

Using the incorrect transmission fluid in any transmission will drastically shorten the service life of the transmission.

True, an abused transmission can fail shortly after a fluid change. I have seen it happen. However, the reason for failure is not the fluid change, the cause of the failure was the previous abuse created by failure to perform routine maintenance fluid changes. Old dirty/contaminated trans fluid does not "hold together" a high mileage transmission, it simply allows excessive wear and slippage that generates heat. The fluid contamination and the heat are what destroy the transmission. High mileage transmissions should be regularly serviced just like any other transmission.

[srmitchell]

I think it's a waste to use synthetic oil in the aw4 and 231 tcase. I use literally any type of dex/merc 3-4.

They aren't picky about brand but you do need to change the fluid, and running an aux cooler is wise.

I just changed my tcase fluid after 20,000 miles. Too long. It had lots of silver, but no chunks or anything.

[DerMeister]

I've used Valvoline Dex/Merc III in my AW4 and all seems well. Only 10k since I dropped the pan and replaced the filter follower by a few drain and fills.

[-Rudy-]

I'm not a firm believer in synthetic oil since I change my engine oil every 3k miles and the tranny/axle fluid every 10k.

Royal purple is a gimic when it comes to jeeps. You will never notice a difference in oils.

I can't even tell the difference in my S2000, and I track it. Put a good quality filter on the engine and tranny if it's auto, pour in some good conventional oil, and have a nice day.

Synthetic oil is just asking for leaks and BS to start popping up.