Engine/Transmission (1998.5 - 2002) trans hunting between shifts

[capt steve]

my trans keeps shifting back and forth between 2nd and 3rd from 33 - 35 mph and between 3rd and 4th from 45 - 53 mph. i changed the fluid and flter also the trans speed sensor
any ideas. thanks

 

[JLandry]

Did this just start suddenly or ???

John L.

 

[JJPage]

Governor pressure solenoid and sensor.
Here is a "how to" with pics from CF, and resources for purchase.

http://www.cumminsforum.com/forum/9...-47re-governor-solenoid-sensor-swap-pics.html
http://www.electricaladvantage.net/rehdsolenoidsensorkit00.aspx
http://www.transmissioncenter.net/dodge.htm

 

[Bob4x4]

Is this at a steady light throttle cruise?

 

[FCrowder]

How many rpm's does it change? if it's only 200 - 250 it might be the tourque convertor lock unlock problem.

 

[capt steve]

yes i just started happening about two weeks ago. if you travel in those mph ranges it will jump rpms about 100 - 200

 

[SnoKing]

Look at the end of this thread. I list a bunch of things that can maybe cure torque converter lockup hunting. Fixes vary truck to truck. Cleaning all the grounds in step one.

https://www.turbodieselregister.com/threads/241693-Couple-new-issues!/page6

 

[cerberusiam]

TC is probably locking\unlocking. A fun issue to resolve.

 

[SnoKing]

Tell me!!!!!!:{:{:{ Snoking

 

[Bob4x4]

yes i just started happening about two weeks ago. if you travel in those mph ranges it will jump rpms about 100 - 200

That is what I expected to here.you are looking at an electrical noise issue locking and unlocking your torque covertor.Many possibilities as to the actual source.I would insulate the ground cable that runs over the alternator with a few layers of tin foil then wrapped.Vitually free and may be as far as you need to go.You can also run a separate ground wire between the right side batt directly to the pcm,again without opening your walletTher was also a flash iirc for 99-2000s for this issue that corrected some trucks

.

 

[JJPage]

How many rpm's does it change? if it's only 200 - 250 it might be the tourque convertor lock unlock problem.

Look at the end of this thread. I list a bunch of things that can maybe cure torque converter lockup hunting. Fixes vary truck to truck. Cleaning all the grounds in step one.

https://www.turbodieselregister.com/threads/241693-Couple-new-issues!/page6

That is what I expected to here.you are looking at an electrical noise issue locking and unlocking your torque covertor.Many possibilities as to the actual source.I would insulate the ground cable that runs over the alternator with a few layers of tin foil then wrapped.Vitually free and may be as far as you need to go.You can also run a separate ground wire between the right side batt directly to the pcm,again without opening your walletTher was also a flash iirc for 99-2000s for this issue that corrected some trucks

.

That was a great question FCrowder asked about RPM movement...changed the dynamics of the issue to TC locking/unlocking instead of actual shift changes occurring. That kind of inquiry and attentiveness to your issue is what makes this Forum the best. But now the work begins Jess

 

[JR]

The correct fix IMO is to test the altenator for AC noise. Anything over about 0.1 volts AC and you likely have a bad diode(s). AC noise can affect other sensors as well but the TC lock/unlock seems to be the first place it shows.

For a quick check you can also pull the main altenator fuse and take it for a quick drive to see if your shifting problems persist. If it resolves it the altenator is your problem.

 

[capt steve]

Thank you all very much. i tried diconnecting the alternator fuse nothing changed. then i wrapped the ground cable going over the alt in foil the cable was also resting on the alt and i moved it away from it with a wire tie. i also ran a ground wire from the right side battery to the PCM and it seems to be working. thanks again everyone

 

[Brando55]

Thank you all very much. i tried diconnecting the alternator fuse nothing changed. then i wrapped the ground cable going over the alt in foil the cable was also resting on the alt and i moved it away from it with a wire tie. i also ran a ground wire from the right side battery to the PCM and it seems to be working. thanks again everyone

I am having this same issue. Just wondering the location of the PCM so I can give this a try myself.

 

[JR]

Wrapping the cable is only masking the real problem. I'd suggest testing the altenator as I mentioned in one of your other threads. Lots of band aid fixes out there and most of them are temporary.

 

[BTMaltby]

Another problem that no one has mentioned yet is a broken accumulator piston return spring. It is an easy access on the bottom driver side of the valve body; there is a small metal plate with five screws and a wiring retaining hook on one end. When I fixed my transmission I found mine was broken. According the you tube mechanic I watched doing a transmission teardown and inspection this a common problem that causes hunting between drive and O/D.