1991 V6 Transmission Control Module question

[Matthew Cody]

A few months ago I was out at the junkyard getting a few things, there was a 89 V6 minivan that had a newer Mopar reman TCM with the latest software so I grabbed it knowing these updated modules improve the general operation of the A604 transmission. I installed it in my 91, it works fine but I have NO lock up function, engine sits at 3500 RPM at 65 MPH. According to the TSB I read, the proper updated TCM number is 4796121 which is the one I have. Is there some kind of modification I have to make to get the lock-up function to work again? The old module works fine, I just grabbed this one because I know these parts are getting scarce and it would be nice to have the latest software to prolong the longevity of the A604. Already did a fluid and filter change with ATF+4 and a genuine Mopar filter. 

Thanks

Edited July 22, 2019 by Matthew Cody (see edit history)

[Reaper1]

If it's a reman unit, are you *positive* it's a flashable one?

 

Personally, I would stick with the one that the car came with, but update the solenoid pack and the sensors/pigtails.

[Matthew Cody]

Yes it's the flash-able one. I used my Snap On scanner to do a quick learn on it prior to the test drive. It shifts just fine, just no lockup function. I did read about a wire that needs to be cut at the connector (if it has it), I need to inspect my TCM connector if it has that wire. 

[Reaper1]

Oh yeah...I remember that...I think it had something to do with the partial LU function that was causing shuddering.

[Matthew Cody]

I'm not terribly worried about it, my current TCM works just fine, probably the best shifting A604 I've ever owned probably due to it's super low mileage and fresh ATF+4. I'll scope around the connector and see if it has that PIN. I grabbed the TCM because finding any 1995-older Mopar in the junkyards is hard, let alone a 89-91..need to stockpile hard to find parts.