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2004wjmedic 07-27-2011 06:40 PM

HELP! Transmission issues?
Hello Everyone,

I have a 2004 Jeep Grand Cherokee with the 4.7L. Today it's starting acting weird. It was fine this morning but then this afternoon when ever I would start off from a dead stop it would be "jerky" with the tack going up to around 1200-1500rpm and back down to idle two or three times and then start going like it hadn't done a thing. I'm confused about what this might be because once on the move the Jeep is just fine and shifting normally. I ran the key diagnostic check and it came back with no codes and just said "done". Low transmission fluid (I checked it and it did not smell/look burned but maybe a tad bit low but not to the add line) ? Throttle postion sensor? Torque converter? Hopefully it's nothing to serious. Any suggestion or ideas would be greatly appreciated.

Frango100 07-27-2011 10:01 PM

Re: HELP! Transmission issues?
Did the tach fall back to idle with the accelerator pedal in the same position? The tranny didnīt shift in the meantime? If you have a scanner, you could check the TPS output. On mine its around 12 % in idle and should go up fluently without spikes up or down when pressing the accelerator pedal. When spikes are present, it probably is your TPS.

2004wjmedic 07-27-2011 11:08 PM

Re: HELP! Transmission issues?
My foot & the pedal stayed in the same postion while the tach went up and then back down to idle This occurs two to three times and the tranny does not shift out of first when it does this. Once the Jeep gets over its fit and underway it seems to shift normally and to drive normally. This is what made me think that it was possibly the TPS. I don't have a scanner but I'm going to try and get it to the shop tomorrow.

01grand 07-28-2011 09:02 AM

Re: HELP! Transmission issues?
Definitely sounds like how mine behaved when the TPS went out, but could be something else too. If it is the TPS its about a 15 minute job to replace, very easy.

2004wjmedic 07-28-2011 11:37 AM

Re: HELP! Transmission issues?
Thanks for all the comments! I took it into the shop today and they took it on a test drive and of course it behaved for them. I then took it on a test drive with them and it did it once. They said that it may be the TPS or a speed sensor but because it only did it once it was extremely difficult to diagnose it. So rather than just replacing parts and wasting money just to drive it until the Jeep throws a code. So thank goodness for an honest mechanic that isn't going to try and gouge me for money but it sucks that they couldn't figure it out today. I'll keep everyone updated.

CaptinCork 07-28-2011 12:06 PM

Re: HELP! Transmission issues?
For what this may be worth. I have a 98 GC 5.9 LTD. Have replaced most everything major (including the TPS at 268K) on/in the 300K I owned it. The beast still performs well. Your description reads precisely as I experienced the TPS issue. My sensor acted up at approx 45 mph and again at 68 mph. Consequently at hwy speed (68 mph), I also noted the prm surge with the cruise control engaged. Made the diagnosis a little for difficult. On my 98, it never did throw a code. After the cruise control sys checked out I went for the TPS. Replacement was straight forward. Cleared up the issue. Good luck.

01grand 07-28-2011 03:14 PM

Re: HELP! Transmission issues?
Wow an honest mechanic, keep his number handy!

Sounds just like what happened to mine, it was acting funny, threw a code while camping out in the woods (luckily my dad had his code reader with). I cleared the code, and only had very intermittent problems for the next 9 months. Then one day on the way home from work it started acting up horribly, threw the P0121 (TPS error) code, and I stopped at Advance on the way home. $35 and 15 min. of work later it was good as new! Good luck, I hope whichever part it is doesn't fail at too bad a time! (not that there is really a good time for a failure haha):thumbsup:

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