Edmunds Answers

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  • avatar landscaper1968 02/18/09 10:09 pm PST

    I searched hi and lo for a cheap Throttle Position Switch. Everything I read was pointing me in that direction. I talked to a guy that told me to cut the Ground connection harness out and make a direct splice before I do anything.
    OK! The part I am talking about is for my 1998 1/2 Dodge Cummins 24v (8th number in V.I.N. is 6) 3/4 ton Quad cab. It is located on the passengers side battery tray. Look at the (Black) Ground cable comming off of the battery- there are 3 wires ranging in gauge. One is the battery cable which drops down below the engine, one mounts to the engine compartment and the last one jumps to the alternator with problem connector. It is mounted to the battery tray with 2 plastic push clips. I was told to cut out the connector and make a direct splice. I opted to pull the harness apart first and work to insure a good connection. PROBLEM FIXED! Took 5 minutes if that.... My truck had been shifting in and out of overdrive between 43 and 48 mph for months and started getting worse lately around 50mph. From what the "Stealership" told me, that connection has something to do with the Ground to the tranny to lock up the torque converter. Hope this helps someone. Saved me hundreds of dollars. Try it first! FREE and SIMPLE........ Good Luck!

Answers

  • karjunkie 09/21/08 9:18 am PST

    Only the ECU/TCU modules control the shift points on a modern transmission. A TCU generally uses sensors from the vehicle as well as data provided by the Engine Control Unit to calculate how and when to change gears in the vehicle for optimum performance, fuel economy and shift quality. So I highly doubt any change in the electrical connections or ground points will do anything but fry your electrical harness and possibly damage your transmission's electronics.

  • mark1969 10/16/08 10:53 pm PST

    I had the same problem with my 1999 Dodge 2500 diesel truck and it ended up being the alternator that was causing the shifting between 45/50. It was sending an electrical spike to the computer.

  • landscaper1968 02/18/09 10:09 pm PST

    I searched hi and lo for a cheap Throttle Position Switch. Everything I read was pointing me in that direction. I talked to a guy that told me to cut the Ground connection harness out and make a direct splice before I do anything.
    OK! The part I am talking about is for my 1998 1/2 Dodge Cummins 24v (8th number in V.I.N. is 6) 3/4 ton Quad cab. It is located on the passengers side battery tray. Look at the (Black) Ground cable comming off of the battery- there are 3 wires ranging in gauge. One is the battery cable which drops down below the engine, one mounts to the engine compartment and the last one jumps to the alternator with problem connector. It is mounted to the battery tray with 2 plastic push clips. I was told to cut out the connector and make a direct splice. I opted to pull the harness apart first and work to insure a good connection. PROBLEM FIXED! Took 5 minutes if that.... My truck had been shifting in and out of overdrive between 43 and 48 mph for months and started getting worse lately around 50mph. From what the "Stealership" told me, that connection has something to do with the Ground to the tranny to lock up the torque converter. Hope this helps someone. Saved me hundreds of dollars. Try it first! FREE and SIMPLE........ Good Luck!

  • mrdolphin2u 03/22/11 11:03 am PST

    I fixed it using this solution about 8 years ago

    http://www.kentsoil.com/dodgebug1.htm

    98.5 24v @ 295k original trans still going strong.

    HTH

    Source: http://www.kentsoil.com/

  • ramphil 10/12/11 8:14 pm PST

    My1998 did the same you need to isolate the ground wire coming off the passenger side battery that groups in with the wiring harness under the alternator and then sheild it. I cut mine and pulled it out of the harness just up to the front of the valve cover and routed it above and away from the aternator, and also had an old stainless braided hydraulic hose in the garage that I slipped over the ground wire to sheild it from the alternator. I then meshed the ground wire back where I cut it and soldered it. Truck drives better than when it was new. The electronics that control the shift and your throttle can get voltage from the field coming from the alternator. let me know if it fixes it
    phil.

  • newjoe 01/26/12 7:53 pm PST

    I have the same truck with the same problem. It doesnt happen all the time but I know what your dealing with . I have been told the 4-5 wires you r talking about re-grounded I cant help tell you where to find them but if u do try to ground them better hope this helps save u some $$$$


  • wooten1026 04/28/12 5:07 pm PST

    The problem is actually the voltage regulator on the back of the alternater itself. It causes the TPS, "Throttle Positing Sensor" to lose power, therefore causing a short. On some alternaters the voltage regulator can be replaced. Best bet is to replace the whole alternater, saves you money in the long run.


  • chuckemoss 07/11/12 8:13 am PST

    I have an 1999 dodge 2500 with a 5.9 Cummins that is and has been doing the same thing. you better have the ground cable on the battery on the passenger side very tight & no corrosion. If corrosion gets into the cable you will have problems. don't know what causes the problems but it is between the negative post on the battery on the passenger side and the alternator and the Throttle Control Sensor. And if not fixed it will destroy your transmission. although it did take 75,000 miles on each transmission. I am on number 3 now.


    Source: 

  • plain_old_me 04/22/13 10:55 pm PST

    I had the same problem with my 99 dodge diesel. I took it to a tranny shop and they found the speed sensor was bad as well as a belt that comes off the tranny that also controls the shifting. Total bill for their work was around $125.

  • ramphil 05/16/13 9:13 pm PST

    the problem will go away if you move the ground wire from pasenger side battrie that goes up around altinator and into wiring harnest
    the altinator is causing interferance with sensor wires going to computer

    i put mine inside a piece of braded hydrolic hose it worked like a charm
    no more shifting problems

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