I've uses synthetic ATF (currently Amsoil) in my wifes 96 Cherokee since new. It currently has over 160K on it and has been used to tow frequently in the past (up to 3000# on occasion).
I had a transmission cooler installed when it was new and never have had a problem with it.
Have a 99 Cherokee with the 4.0L and the AW-4 tranny behind it.Bought this vehicle new and currently have 202560km on the odometer.Been using Mobil 1 ATF in the tranny for years and it gets worked every fall with the moose hunt coming up in a few days from now.Towing around 2000lbs 16 hours,then off roading for 9 days,then pulling my crew and equipment plus a nice bull (hopefully) another 16 hours back.This trip is not on flat surface highways so alot of shifting, even with the auto ,is needed.Been doing this trip with my XJ since I broke it in new and it runs better than the day I got it from the dealer...by the way I ordered the tow package with it in 99.
Depends on the vehicle. The above comments seem to be for Jeep Cherokee models which use the AW4 auto (basically a Toyota auto trans). The 4.0 Grand Cherokees use a Chrysler auto tranny that has shown to be much more problematic and is not nearly as durable.
Like they said, the AW-4 is bulletproof. The tranny in the grands in one of their major weaknesses.
I would be more concerned with the axles, suspension, and rear brakes, probably the biggest weaknesses of the XJ. I had both axles rebuilt under warranty when I bought my '01 used, and I put a teraflex rear disc kit on. Now the axles are quiet and it stops as well as our subaru. I'm still not satisfied with the suspension, something is fairly loose. Supposedly the newest of the post '97's have soft bushings. I haven't dug into that one yet, I have some lift springs and new bushings ready to go into it, along with the coveted 242 t-case. Maybe the trackbar is loose. Now I just need the time.
The 4.0 and AW-4 are bulletproof even with sub-BITOG maintenance practices.
If I had to do it again I would look for a '98 or '99 with upcountry suspension and an NV-242 t-case, very rare but I think that's the sweet spot.
If I remember correctly the manual tranny has a 2k lb towing capacity, while the auto has a 5k lb rating. I wanted a manual, but the fact that they are difficult to find and the towing rating steered me to an auto.
NAXJA will have all your answers.If the Grand Cherokee has the 4.0L in it the AW-4 should be behind it...it's the Grands with the V8's that had the Chryco trannies.I believe up till 01 the XJ had the AX15 standard behind the 6 and AX5 behind 4 banger after 01 the NV3550 replaced the AX15.The AW series were an agreement between Aisian(Toyota tranny producer)and Borg-Warner hence "AW".The AX series of standard trannies were a spin-off agreement of the same companies.NV series trannies are made in the U.S.A by New Venture that is now Magna Internationl and are pretty good also.They (NV) make transfer cases for numerous vehicles of all makes and have a good reputation.
The 4.0 Grand trannies are pretty good if you change the fluid and filter every 30,000. The only real issue is the governor solenoid and pressure sensor sometimes need replaced. It's a simple job. And ONLY use Mopar ATF+4.