If you remember, I asked awhile back about lock up. My truck wouldn't lock the converter. Took it to a shop and the mechanic said everything seemed ok and couldn't tell me why it isn't locking. I took it home and changed the fluid/filter. Not too much junk in the pan. Now when I drive the converter locks briefly at about 48mph and then seems to go right back where it was (unlocked). It does this about 3-4 times until the truck warms up and I can't feel it try to lock up anymore. The TPS voltage is at about 1.2-1.3. Any ideas why it won't stay locked? Fluid level is right on. All help is appreciated.

 

You may not want to hear this, but I lost the TCC facings, did you have black fine debris in the pan and on the filter?

Easy way to check is to put a temporary gauge in the tranny cooler line and be able to monitor it while driving. TCC lockup increases pressure in that circuit.

That is how I finally diagnosed mine, Dave G. turned me on to that trick.

( I had a DRB at my disposal, so I could have someone command LU while I squeezed the hose )

Good luck

 

Could be your tranny temp sender is messed up.
It's easy to check on a RH tranny but I'm not sure how you do it on a RE such as yours.

 

Does a 96re have a tranny temp. sender? I put one in for my guages but don't think there is a stock sender???

 

There is temp sender internal to the RE. It signals the idiot light when the tranny overheats and won't allow TC lockup if the fluid temp is below 70 or above 220.

If you have your after market tranny temp sender in one of the test ports on the tranny it could be the cause of your problem if the probe is too long and extends into the tranny. Not sure what the exact problems this causes though, just been told by the diesel tranny experts that using the test ports can cause damage.

 

There are a lot of factors to allow T/C lockup. The TPS and trans temp sensors and speedo are all inputs to the PCM. If any of them are failing, you can have electrical noise that will not allow lockup. There are ways to bypass them.

Let me suggest that you look up the wiring diagram for a T/C lockup switch and install one. If it works, you know your trans is basically ok. If it does not work, then you have an internal problem.

There is a current thread on here with the diagram. Remember, the RE diagram is different from the RH diagram too.

Ronnie

 

Lock up switch is an excellent suggestion.
Install is simple, instructions> http://www.tstproducts.com/Torque%20...p%20Switch.pdf

Only problem might be that the switch doesn't always work on a '96 without a dealer PCM reflash.

 

Part No. 04886926.
Thats the part number for the flash in case your local dealer cant find it

Its needed for early 1996 model years up to Feb I believe , so the lockup switch will work

 

Yeah, I tried the lockup switch and my truck is the one that needs the reflash. I will call a Dodge dealer in the morning to see about a reflash. Thanks for the help guys!!!