Engine/Transmission (1998.5 - 2002) Transmission Continuously Slips In and Out of OD

[zgordons]

I have a 1998 Dodge Ram 24 valve Cummins 4X4.

I took it in to a transmission place just to get the transmission oil changed last summer because I was getting ready to haul a 5th wheel trailer to Baja. The transmission was fine before the service, I just did it as a precaution. Instead of just doing the standard partial oil change I had them flush the whole system and do a complete transmission oil change just to be on the safe side.

Apparently that was a mistake.

Immediately after the service I noticed the transmission starting to slip in and out of overdrive under a narrow load range. I took it back to the transmission place 3 times to have them reinspect but it never really went away. Someone guided me thru trying to do a "TPS" reset by unpowering it and it "seemed" to help some but not completely and not permanently.

I was burning up my vacation time screwing around with it and ended up hauling the trailer down without any problems, the problem was minor then and I was out of OD most of the time anyway.

Anyway the problem has persisted and now almost a year later it is getting a lot worse.

It now slips in and out of OD continuously and under a wider range of loads. Basically OD is unusable at this point

#@$%!



Any assistance is greatly appreciated.

Thanks in advance... .

 

[JLandry]

Greetings,

Are you sure the torque convertor clutch isn't just locking and unlocking instead of the transmission actually shifting in and out of 4th gear?

I ask because the phenomenon of the torque convertor locking and unlocking is a common problem which occurs when electrical noise is present in the truck's wiring connected to the PCM (Powertrain Control Module). Electrical noise is often caused by worn brushes or leaking diodes in the alternator. This can be corrected by either repairing or replacing the alternator. You can buy a brand new (not rebuilt) alternator on eBay for under $200, so if your truck has lots of miles, this may be a good thing to do anyway as a preventive measure.

It could just be coincidence that your transmission started acting up when the fluid flush was done.

Please keep us posted,

John L.

 

[cerberusiam]

Any other sysptoms form the trans, hand shifts, late upshifts, shuttle shifts on 1-2?



APPS are a big problem on your truck and frequently cause the issues you describe. The gov pressure solenoid will do this also so there can be mutltiple sources.



If it is actually dropping out of OD it could still be noise from the alternator causing it like the lockup problem. A cheap easy way to test that theory is find the wire from the passenger side battery that runs across the top of the alternator and wrap it in tin foil from the battery past the alternator. That will isolate the wire that is introducing the noise intot he system.

 

[zgordons]

I've had the truck for 10 years and it has 75,000 miles on it.
Just seems too coincidental that the problem started when I was driving it away after the transmission oil flush.
Not sure how to tell the difference of it being the torque converter vs the transmission but it does only occur between 3rd gear and overdrive.

When I disable OD the problem ceases...

?????

 

[cerberusiam]

You get about a 200-300 rpm drop when the TC locks\unlocks. OD in and out is 600-800 rpm difference and a lot of noise change.



Gov pressure solenoid is the usual culprit after a fluid change\service.

 

[ALepley]

Try the ground rewire for the apps. You can find the info on suncoastconverters.com

 

[firefighter_2000]

Also

I did the suncoast rewire... Didnt do much... Added the DTT noise filter and have had ZERO problems since then. I have to agree with the guys above. Sounds like the TC hunting problem. You say it dissappears when you kick it out of OD. Try the same RPM range in third and see if it happens there. Mine would do it, just at a slower speed but same engine RPM.

Craig

 

[DFerverda]

You get about a 200-300 rpm drop when the TC locks\unlocks. OD in and out is 600-800 rpm difference and a lot of noise change.



Gov pressure solenoid is the usual culprit after a fluid change\service.

Is there a gasket under the governor solenoid/sensor body, or is it a machined fit????

 

[cerberusiam]

Is there a gasket under the governor solenoid/sensor body, or is it a machined fit????

There is a gasket under the governor housing but it doesn't neccessarily need to be removed to change the solenoid. Its not a bad idea to remove the housing and clean everything though which will entail using a new gasket.



There is a newer heavier duty solenoid available that has show some promise for better reliability or there are aftermarket solutions that have shown to be better also.



Again, this is only going to be effective if the truck is actually intermittently loosing OD and not suffering from the TC lock\unlock problem. It may not cure an OD issue either as there are other things that could be causing it.



Given the problems started after a trans service, the gov solenoid is highly suspect.

 

[DFerverda]

I have a post on the first page, no response from anyone,(JLANDRY did send me the 47re out of the book) My problem is it does not want to shift out of 1st unless you back off the go peddle, then all is well i bought a solenoid and a sensor but didn't want to take things apart without finding out about the gasket... ... ... .

 

[cerberusiam]

I have a post on the first page, no response from anyone, My problem is it does not want to shift out of 1st unless you back off the go peddle, then all is well i bought a solenoid and a sensor but didn't want to take things apart without finding out about the gasket... ... ... .

Sorry, mixed up threads. :-laf



Thats a one of the symptoms of the solenoid going south also. It could also be the sensor so the normal routine is replace in pairs. I pull the gov housing the first time and clean everything well just to be sure so a gasket is needed.



FYI, I get about 40k out of a set then they start acting up. However, I am running way more pressure than normal.

 

[FDavid]

This is taken directly from the TDR Buyers Guide:



"Glitch: My automatic is too automated.

Fix: If your automatic transmission truck changes its mind

a lot about what gear to use, don’t start with the gearbox,

but check the throttle position sensor. The letters TPS are

as well known to readers, as this infamous part could be

a major nuisance. The TPS failure is characterized by a

100-200 rpm swing as the torque converter clutch locks and

unlocks repeatedly while the transmission remains in 4th

(overdrive) gear. Clean it and the connectors yourself or get

a new one; chances are if it hasn’t gone bad, it will.



Do not confuse a TPS failure with a TTS (Transmission

Temperature Sensor) failure, which is characterized by a

200-400 rpm swing as the transmission cycles between 3rd

and 4th gear. Replace the TTS and check the connectors

for corrosion. The downshift is made when the failed TTS

sensor says the outside temp is below –5° (zero volts). The

upshift is made when the TTS again sends a signal (+1

to +5 volts) to the PCM saying the outside temp suddenly

climbed to ambient temp, thus allowing overdrive to be

engaged.

Ref: I 37, p 46"



If it is the TC locking and unlocking (usually between 40-50 mph), there are a few things you can do that will usually correct it. These include checking to make sure both batteries are good and their grounds are tight, wrapping the alt to battery wire in foil and most importantly checking and adjusting the voltage on the TPS.