OT 1999 Dodge Ram shifting problem

LeoinMI · Mar 30, 2010

I know this isn"t tractor related,but thought someone might know why my Dodge Ram is shifting funny as of late. The RPM"s go up and down @ 55mph-60mph. Never did this before. Is it maybe the throttle sensor up on the engine by the throttle body, or the shifting sensor down on the transmission? Can it be something more major like the torque convertor? Tranny fluid is clean (not burnt) and full. It is an automatic transmission 4x4 360 c.i. engine.The tranny shifts fine in all four gears up to about 55 mph,then the RPM"s go up and down on their own witout pressing on the accelerator pedal.
Thanks for any help,
Leo

Dblair · Mar 30, 2010

is it gas or a diesel , diesel it's a tps probally the same thing in a gas. throttle position sensor. try taking the battery cables of and cleaning them real good clean all the wires connected to the cables and clean the ground.

Wardner · Mar 30, 2010

I have a '98 Dodge Cummins w/auto trans. I had the same problem. Threre is a revolution counter at the front of the engine. One of the wires going to it became frayed by the fan belt running close by. I replaced the belt and repaired the wire. That's all it took to fix the problem.

Roger in Iowa · Mar 30, 2010

Just had my transmission, transfer case and diffs oils changed and bands adjusted. Really changed things at 91,000.

Also later changed throttle position sensor and it got rid of the lockup torque converter coming and going.

BCnT · Mar 30, 2010

can you actually hear engine revving up or you just going by tach?
if engine is actually revving up it could be a loose connection in torque convertor lockup in overdrive or a bad speed sensor.
if it seems to be just the tach,there could be any number of things causing it to fluctuate

omahagreg · Mar 30, 2010

I have heard if an engine misses (needing a tune up) it will show up as you described at highway speeds. Greg

wally_mi · Mar 30, 2010

had the same prob. on my old dodge. a new fuel filter would cure it . hope you can cure it as easy. wally

LeoinMI · Mar 30, 2010

Thanks for all the help guys. I forgot to say the engine is gas and I had new plugs,wires Distributor cap,rotor ect..about 8,000 miles ago.The engine does not miss and really gets up and goes when you step on it, (i.e no fuel flow problems)and the tranny shfts fine. Also I can actually hear the RPM's increase,not just seeing the tac going up over 2,000. This occurs during normal acceleration only.
From what I read, I figure it is either the speed sensor,Throttle position sensor,.or a loose connection in the torque converter lockup preventing it from operating correctly.
I'll re-check for frayed wires,(doesn't appear to be any that I can see at this time) The sensors are a relative inexpensive fix. I'll buy new ones from NAPA and replace both.If that doesn't fix it, I may have to go to a Transmission shop ($$) to check the torque converter.
Thanks Again,
Leo

sotxbill · Mar 30, 2010

bad ground under battery tray will cause the torque converter to lock and unlock due to voltage rise. clean and reground chassis and engine.. especially at the alternator.. Make sure its got a good ground. known problem with automatics.

skycarp · Mar 30, 2010

Leo,

I have a '98 Ram with automatic transmission. What I hear you are saying is your transmission is hunting for direct drive or overdrive. This is a very common complaint from Ram owners with automatic transmissions from that time period.

Over the years this has happened to me three times. It happened when I was up to speed and around 55 mph. Twice I cleaned the ground connections at both batteries (it's a diesel) and solved my problem for a few years. The third time I had the transmission shop put in a Wiring Filter to solve the problem for ever ($10.00 cheap).

What is happening is the electrical controls for the transmission is sensing electrical 'noise' around the wiring from/to the TPS. This noise is usually comes from a bad ground. This 'noise' is telling the transmission to shift either to direct or OD.

If I were to have this for the first time I would just have the electrical noise filter put in the line.

Dean

LeoinMI · Mar 30, 2010

Thanks Dean. I'll look into installing a wiring filter. Also thanks to sotxbill for the advice on the ground connections. Sounds like the problem may be two fold with the wiring and the throttle sensor. Both fixs shouldn't be too bad. I can put the sensor in myself and clean all the ground connections also. Don't know the cost of installing a wiring filter, ($10.00 + labor) shouldn"t be too bad.
Again,thanks for all the help
Leo

Jeff B. · Mar 30, 2010

I don"t want this to sound like a plug for my company, but I"m going to tell you anyway....
I work in a transmission warehouse/shop, and one of our techs has determined that the cause of those Dodges hopping in & out of lockup (the fluctuation you describe) comes from rf noise in the wires that run to the transmission. The noise comes from alternator wires in the same loom as the transmission wires. He has devised a noise suppressor diode that is wired in-line and fixes the problem. It"s simple and relatively cheap. If you"re interested, call 1-800-225-6568 and ask for information on our "signal stabilizer". You can talk to our techs, and they will be able to tell you if that will probably fix you problem. Or e-mail me if you"d like.
Jeff

Anonymous-0 · Mar 30, 2010

If you are hearing the engine flare up and seeing the tack just about 200 rpm, replace the tps. They are common for this happening and at this speed. It usually happens at steady speed, most of the time with the cruise on. It is causing the torque convertor to go in and out of lockup. tps has a bad spot , going faster or slower you will not have a problem.

Ryan - WI · Mar 31, 2010

It is the TPS. I have had to do mine twice now on my 99 Dakota with the 318.

OT 1999 Dodge Ram shifting problem

LeoinMI

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Dblair

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Wardner

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Roger in Iowa

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BCnT

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omahagreg

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wally_mi

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LeoinMI

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sotxbill

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skycarp

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LeoinMI

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Jeff B.

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Anonymous-0

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Ryan - WI

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