dave1123

I need some opinions. Mopar ATF+4 sells at my dealer for $8.50 a quart plus tax. After doing some research, I find that Chrysler has certified 38 brands as meeting their standards for transmission fluids.

What is your favorite and how does it compare in cost? I'm ready to be buried in responses.

I'm looking to buy a case for a tranny and t/case fluid change.

blackjack12982

I'm almost ashamed to say it, but ever since I've owned ZJ's, I've always used the cheapest Walmart/O'Reilly's ATF+4. The current ZJ has 5+ years and ~25k miles on the rebuilt 46RH. At the start of each year I do a TC and trans fluid swap and trans filter change for peace of mind during the wheeling season, and have never had a problem. I know it's overkill, but it's worked for me. I think more important than fluid brand name is having a trans cooler and a temp gauge for summer wheeling.

dave1123

Believe it or not, O'Reilly's is on the Chrysler approved list! I used to work for Valvoline so, of course, I checked them first. Napa has it for $6.99/qt. I will check O'Reilly's also. Thanks for the tip.

According to the records I got from the PO, my 42re got a T-Tech (direct transfer) at 121K but I doubt the filter was changed. It's got 156K on it now and I want to do a filter change, replace the torque converter solenoid, and a complete fluid change soon. It's setting a P0740 code about once a month. The shifts are smooth and solid and on time now and I want to make it last as long as I can.

I just put new axle bearings in the rear because one seal was leaking and I used Valvoline 75W140 Synthetic lube in it. I have the 242 t/case so what do you think about using the same lube in the front diff?

blackjack12982

Hmm, good to know about the O'Reilly's fluid. I bought my ZJ with ~174k miles on it, and I had no records of any service for anything. The 46RH to my knowledge lasted 175k miles.

The fill spec for the transfer cases is AT+4 also, I don't know if that's what you meant. I've seen some reports that people have used gear lube or thick motor oil, but from the factory, they're supposedly ATF+4 filled. Also, make sure you pull the fill hole plug first.

dave1123

No, I only mentioned the t/case because it's seldom driving the front diff. I know the t/case uses ATF+4. I just thought there'd be less rolling friction in the front if I used synthetic. Besides, I have almost a full bottle left from the rear fluid change. I think my book calls for 90W in the front diff, but that stuff gets like tar in the cold.

I've serviced all these cases when I worked for Valvoline Instant Oil Change so I'm ahead of the game. The plugs are 10mm also, not 3/8 like everyone thinks.

blackjack12982

Ok, I didn't know if you were tempted to throw the gear lube in the TC as well. Yeah, I think my 94 manual calls for 75W90 for the diffs, but it doesn't get near as cold here in the South. I know some people have said to run 75W140 in the rear if you have an LSD, I'd be pretty certain that it's not really a big deal as long as the right amount of fluid is in there.

dave1123

Yeah, Valvoline's synthetic has the LSD additive in it. It's just a friction modifier to allow the clutches to grab better.

I found out something recently. Did you know that at one time Ford's Type F tranny fluid had grit in it to help the clutches grab? OMG!