I've got a 98 4.0 Wrangler. I bought it about 2 weeks ago from a guy who hadn't ran it in a year. I want to replace all the fluids just so i know what is in there! It has already had the radiator pulled out and pressure flushed because it was full of crap, the oil has been changed as well. The Power steering fluid looks good from the dip stick so i was gonna leave that alone too.
I want to drain and replace the Tranny fluid, transfer case, and both diff. fluids...
I got the haynes Jeep Book but I still have a few questions...
It says to use SAE 75/90 gear lub for the Tranny. I was thinking of getting some Royal Purple Manual transmission fluid instead... Is this ok or should i just get the Royal purple 75/90 fluid? I just heard that Royal Purple was the best and For a few bucks, i thought I would add that...???
Transfer Case - will any ATF work?
Diff... It doesn't say how much??? And Should that also be 75/90 Gear lub?
I am not sure if the length of time sitting matters which I will leave to the experts but I have change most of my fluids to Royal Purple. I wasn't able to determine if you are using auto or manual. I am using manual. This is what I use:
Transfer Case: Synchromax
Diffs: Max-Gear 75W-90
Oil: RP 10W-30
Radiator: Purple Ice
Later on when I flush my power steering I will replace it with Max EZ.
All of this can be expensive but look for sales. Most places will price match competitors which saves driving. Recently I was able to buy 4 qts. of oil and the filter for $40. I bought double for the next time.
The other stuff I bought at the local 4Wheelparts store. They gave me a big discount compared to Pepboys and Checkers here. It was about $4 a bottle difference.
To find out what my Jeep had, I took my VIN to the dealer and they printed out the specs of all the parts and options.
Look on page 1-2 of the Haynes manual. It will show capacities.
Here is a couple thoughts to consider, if you are going to wheel this Jeep, going with a high $$ lube like Royal Purple in the diffs maybe a waste of $$. Seems that my diff covers come off on a regular bases, water crossing, repairs, etc., so for me, the lube in my diffs doesn't last long anyway.
Also, the OEM radiators are known to rush from the inside out, so the flush maybe only a temporary fix. If you are not careful, the junk from the radiator will plug the heater core.
If you haven't already joined a good 4x4 Club in your area, you need to do so. You will meet a lot of good people, and you will learn a lot. Sometimes the best thing you can be is a wrench boy for someone. If you have an issue with your Jeep, do a search. You will probably find the solution to the problem as well as a step by step write up that walks you thru the repair process. Stu's Web site is good, but there are others. I have also found some write ups on this site that were second to none.
I know this has been debated in previous post, but the recommended lubricant for the AX15 has been changed to 10w30 motor oil. It's even listed inh the Quadratech catalog as the AX15 tranny lube. Not saying it's the best, just the newest recommendation. I've had it in mine for several thousand miles now with no problems.