RPM Jump !!Help!!
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RE: RPM Jump !!Help!!
ORIGINAL: RSwipe
Hi, I have exactly the same problem just starting on my 98 5.2 4x4. It is almost exactly as you described. I did a 300k round trip yesterday and had a real chance to study the trans behaviour. If im running at about 2000 prm in OD or the same speed without OD it still does it, ie the rpm "jumps up " for a split second and then settles again. The trans works fine other than this little fault. I drove it hard, overtook a few cars during the trip, and really didnt notice any sign of slippage or anything else under hard excelleration. This " jump" in the revs seems to only occur when your at a steady throttle, or i can make it happen by quickly throttling off with my foot. It doesnt do it all the time, you can drive for miles with it not happening. Also, I noticed that it doesnt do it any where near as much on smooth road surface. If you hit a bump it almost always will do it if its during a "jump" period of activity. Also, I first noticed this over two months ago when I was driving home from work. It was during the first snows and at the time i thought that the rears had just lost grip for a second or so on a patch of ice, but two months have gone by without the problem and i can now see that what i thought was loss of grip was this problem beginning. Anyway, sorry if this has got confusing. Did you find out what was wrong with your tranny, or can anyone else shed some light on it ? It is almost as if there is a short in the OD button or circuit - no?
Hi, I have exactly the same problem just starting on my 98 5.2 4x4. It is almost exactly as you described. I did a 300k round trip yesterday and had a real chance to study the trans behaviour. If im running at about 2000 prm in OD or the same speed without OD it still does it, ie the rpm "jumps up " for a split second and then settles again. The trans works fine other than this little fault. I drove it hard, overtook a few cars during the trip, and really didnt notice any sign of slippage or anything else under hard excelleration. This " jump" in the revs seems to only occur when your at a steady throttle, or i can make it happen by quickly throttling off with my foot. It doesnt do it all the time, you can drive for miles with it not happening. Also, I noticed that it doesnt do it any where near as much on smooth road surface. If you hit a bump it almost always will do it if its during a "jump" period of activity. Also, I first noticed this over two months ago when I was driving home from work. It was during the first snows and at the time i thought that the rears had just lost grip for a second or so on a patch of ice, but two months have gone by without the problem and i can now see that what i thought was loss of grip was this problem beginning. Anyway, sorry if this has got confusing. Did you find out what was wrong with your tranny, or can anyone else shed some light on it ? It is almost as if there is a short in the OD button or circuit - no?
have you replaced your TPS its about 20 bucks and is reall easy to change and is typically the problem wen your rpm is juming 200-300 rpm everyonce and a while.
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Record Breaker
Joined: Jan 2006
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From: North Dakota
RE: RPM Jump !!Help!!
You could try changeing your TPS, usually that is what it is, however i had a new one put in mine ($160-----*** rapeing) and it didnt fix the problem. I am currently just letting mine sit and will take it to the dealership when i have nothing better to do.[:@]
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RE: RPM Jump !!Help!!
could be a faulty rpm gauge tripping up every now and then? bad wires.. i drove a dump truck before when the rpm and mph gauge kept acting up. had to buy a 700 dollar instrument panel
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Joined: Feb 2005
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RE: RPM Jump !!Help!!
Ok, so I picked one up today and fitted it while at work. It was very easy, disconected battery, unclipped wire from sensor, unscrewed the two retaining torx bolts and removed the sensor. New one was on in seconds. Reconnected everything and fired her up. 5 min job Took the same root home and on the constant throttle straights and over the same bumps that almost always cause the problem I am happy to report after this first drive - about 20 kms or so, that not once did anything happen! I had a gut feeling that the tranny wasn't giving up the ghost (just yet anyway), and that something was "telling" the transmission to jump about because it was all just too precise every time it happened. Anyway, thanks very much for taking the time to reply to my post. If this "revs jump" raises its ugly head again I will post. Best $85 cdn I have spent in a long time! Sure beats $2500!
Thanks guys and good luck.
Thanks guys and good luck.
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Record Breaker
Joined: Jan 2006
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From: North Dakota
RE: RPM Jump !!Help!!
I wish the TPS was the culprit in mine.......im baffled and almost to the point where i dont even wanna know what is wrong........i hope it is not my Torque Converter, but if its not the TPS or the Torque converter.....idk what else it really could be? ? ?
Joined: Feb 2006
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RE: RPM Jump !!Help!!
I had the same problem also. I had the dealer hookup a diagnostic tool to the computer. Found out that under light of no throttle the TC unlocks. Then when you throttle it locks causing a rise in rpms as the TC locks up. I do a lot of towing and also have notice that it happens too. I was told that it was typical as the TC locks and unlocks due to dirty transmission oil. I replaced my trans oil and it did fix them problem for now.