blue01xj

Friends WJ 4.0 4x4 wont go over 30mph. Thinking TCU, Tq converter, solenoids....... Im gonna go look at it soon to get more details but not sure if the WJ uses a AW4 like the xj's. Never messed with a WJ so new to me.

Any ideas or pointers?
Thanks in advance

SatiricalHen

They don't use an aw4 and all my friends with wjs have trans problems. One is on his second trans still having problems.

andrewmp6

Besides the 93 all other grands use a chrysler trans.But its hard to say whats really wrong with it might be lucky and just low on atf.

dave1123

Yeah, the 4.0 uses the 42re transmission. Is it slipping or not shifting? Do you have any trouble codes? If you read the dipstick, it says to check the fluid level in NEUTRAL. A quart low can do stupid things.

blue01xj

he said if you wiggle or play with the shifter you can get it to change and go over 30 and run 70 no problem. so it now has me thinking neutral safety switch. his is 4x4 with 130K and know of two friends with 2wd wj's that have over 200K with no issues at all so knowing 4x4s get crap in the NSS im leaning that way just dont know anything about the 42re trans. Ive had two AW4's open and rebuilt just the wj think is new to me. Hope to get over there this weekend to see.

Thanks for all the ideas so far

CR-Snow

My buddy has an 04. 4.0 auto with the 242 case. His had very similar symptoms when he brought it home from auction. Turned out to be the transmission computer.

dave1123

The NSS is internal to the transmission on the 42re so it doesn't get crapped up. It's a big round plug switch that screws into the side of the transmission, not exposed like the older ones. I'm thinking shift solenoids or the TCM.

blue01xj

ok tcm will be first thing to check

blue01xj

can i unplug the tcu and manually shift it like the aw4? If manual shifts and drives normal then I would expect the tcu to be bad?

dave1123

No, without the TCM you'll set trouble codes and it'll be in "limp" mode; as in 2nd only. With the 42re, 1st & 2nd are hydraulically shifted and 3 & 4 are electronically controlled. The PCM & TCM work together monitoring manifold pressure, throttle opening, and vehicle speed to control shift points.

blue01xj

thanks dave

rangermonroe

Test the TPS.

GUARDIAN

Is it throwing any codes?

Justin Hand

Okay so I have a 98 grand Cherokee Laredo sport 6 cylinder 2wd. Started having problems with not going over 30 mph before i replaced the old computer (which was causing another problem). So I have replaced the alternator today, hoping that was the problem cause these two codes came up p1594 and p0132. I replaced the alternator and went around the block to see if that fixed the problem, it did not. I need some input on this problem. This was my daily driver