Addison Bevier

I have a 2001 Jeep Grand Cherokee I am having a problem with my transmission and am unable to diagnose it. When I put it in reverse it stalls unless I feather the throttle, when in drive it “roughly jumps” into gear from 1st to second amd from 2nd to 3rd when shifting but when I shift gears myself manually it seems to shift normally. Any ideas?

BlueRidgeMark

Welcome to the forum, Addison. Not quite the right place for your question, though. Technical questions belong in the technical forum. "Chat" is more for yakking about the topic in general. I'll flag your post and mod will probably move it soon. No worries.

We need to know which engine and transmission you have. There are options!

dreadtaylor

Sounds like your map sensor might be bad. Scan it first and see if there are any codes stored in computer

Addison Bevier

Sorry I’m new to the forums. don’t know how to work the website that well yet... I have scanned for engine codes and the only thing to come up was a P0720 code. So I replaced the speed output sensor and nothing changed.

Addison Bevier

I have a inline 6 and I believe I have a 45RFE transmission

BlueRidgeMark

Can't hurt to try adjusting your TV cable, sometimes called a kick-down cable. It's easy, and it's free, and it might solve your problem.

dreadtaylor

It's either, map sensor or throttle sensor.....engine running like **** has nothing to do with any cable attached to your throttle body.. unplug you map sensor and see if it changes ANYTHING. If no plug it back in then unplug tp sensor and I nothing changes it's PROBABLY you re tp sensor.

Noah911

I vote this is a Throttle Position Sensor (TPS) problem.

I would test it first, and then replace it with only a genuine Mopar TPS if it tests bad. Non-Mopar sensors have very bad track records.

BlueRidgeMark

Well, that's interesting, but the OP is talking about a transmission shifting problem. He hasn't said anything about the engine running poorly.

Noah911

The reasons why I believe it may be the TPS causing it is because of how he says it stalls out, and that he must feather the throttle in order to make it work.

(edited):
The PCM and the TCM share the TPS output and it effects the torque converter engagement and the shift timing.

An interesting thing is that a faulty Clock Spring or its wires can also cause these same similar type of issues as well. The Clock Spring can send electrical interference noise on the TPS circuit, and the computer thinks it is the TPS sending a faulty signal is what happens. So, another thing he could try is removing the horn fuse. If the problem goes away after doing this? It means the Clock Spring is causing interference to mimick a TPS fault at the PCM.

Hunter_

The WJ (Grand Cherokee years 99-04) had 3 different transmissions the 545RFE the 45RFE and the 42RE all inline 6's had a 42RE and the V-8's had the other two, with no real difference between them. The 45RFE was an auto 4 speed with an extra planetary gear set essentially making it a 5 speed with an alternate 2nd gear for downshifting, the 545RFE is identical accept they were programed to have a 5th gear, you can actually have your 45RFE reprogrammed to have a 5th gear. A 45RFE/545RFE will not mate up to the 6 cylinder engine.

Addison Bevier

I won’t be able to check the pcm and the tps until I get a new battery this Friday after I get paid. as for tranny details I could only find one set of number on it and I also ran my vin and it said I had a 4 speed 42re automatic. My engine hasn't really ran rough or poorly. it would only stall when I’d switch gears into reverse and a slight lack of power in drive, and the lunging/lurching into gears while driving unless I shift gears manually myself. I don’t really notice the problem... thinking back I also remeber when I’d stomp on the gas and it’d go into last gear it’d seem to lung exatreamly hard into gear. so I’d typically stay away from driving at high fast speeds if I could. And I noticed these problems started up right after I got my jeep stuck in a bunch of deep snow last winter. Then sat most the summer due to lack of money for the project.

BlueRidgeMark

PUNCTUATION!