Where's the TCM?

[FandangoCTR]

So the speedo stopped working, then the odometer. Then the trans. starts slipping. We changed the sensor on top of the rear diff. Nothing. Took off the instrument panel - no cable - all electronic. Okay, lets change the trasmission. Did that. Still slips and no speedo or odo. Hooked up a diagnostic computer to it and guess what? No codes stored in the darn thing. The transmission garage said the TCM is bad. Okay, let's replace that - we'll by one form a parts warehouse or something - certainly not from the dealer $$$. So my question is this: Where, exactly, is the Trasmission Control Module? Under the dash? If so, which one is it? There's an Engine Control Module, too. I just need the part number so I can order it. I'm about ready to drive this thing off of a cliff, but I'v spent all my money on this particular Ranger and don't have any more to spend on a new truck.

-Very, very frustrated in Montana.

1998 Ranger 4x4, 3.0L 4R44E T 4 spd auto. trans (w/ overdrive)

 

[locovaca]

There is no separate module. It is part of the main PCM.

 

[Earl43P]

I can send you schematics (2000) to trace down your VSS signal problem.

Send me a PM with your e-mail address.

FWIW, there have been reported problems with the connector under the driver seat. Corrosion affects the VSS signal since it is a low voltage frequency pulse. Might look there, clean it up and use some dielectric grease. The schematics I send will show you which three wires to check. If your multimeter has a frequency setting (most don't), you could see the pulse.

Anyway, it also matters if you have 4 wheel ABS. I believe the 98 raw VSS signal goes to the 4WABS module and then to the PCM and speedo. See which you have, even though the schematics cover both.

If you don't know how to PM, just click on my username and select Send Private Message.

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