Suddenly won't engage Drive or Reverse

[Meridivs]

This transmission shifted smooth and strong through all gears until today when it stopped all of a sudden to engage either Drive or Reverse. No previous signs of slippage, hesitation, stalling or lack of power whatsoever.

We checked the linkage to the transmission and it works as intended, nothing loose or broken, everything is in place. If there was something slightly different with it from other similar vans we have then it had a slightly delayed engagement in Drive (it took a second to engage it after you moved the lever) - on all other vans we have the transmission go into Drive almost instantly.

Van is a '92 Pontiac Trans Sport/Chevrolet Lumina APV with the 3.1L V6 Chevy TBI engine and a 3T40 automatic transaxle.

Any idea on where we should start tackling this issue?

[robertisaar]

how old is the fluid/filter?
is the TV cable correctly adjusted?

[Meridivs]

Filter is 2 years old ACDelco kit and fluid level is ok.

It's like the transmission isn't getting any command from the driver's column lever but the linkage on the transmission housing is in place & working...

Will check the TV cable. Thank you.

[robertisaar]

if you pull the shifter down into manual 1st, does it engage then? doing so should provide a large increase in line pressure, which may be what is causing a failure to engage. that would be my next diagnostic step, checking what line pressure you see during a line pressure test.

[Meridivs]

Definitively solved the problem by swapping the transmission with a known good one.

Now the TCC has gone south (it comes on ragardless of speed, stalling the engine).

Does anyone know how to fix it without too much hassle with taking the subframe and transmission down again?

[1988GTU]

Either snip the signal wire to it or replace the solenoid (and harness) .

[Meridivs]

I already "pulled the plug". Question is how complicated would be to replace the solenoid on this one (3T40)?

Either snip the signal wire to it or replace the solenoid (and harness) .

[1988GTU]

I already "pulled the plug". Question is how complicated would be to replace the solenoid on this one (3T40)?

Then once it disengaged and followed by pulling the plug at the front facing of car at the trans, it should no longer be functional.

Question is how complicated would be to replace the solenoid on this one (3T40)?

Side pan removal. It should be relatively easy in that Pontiac TS. Beretta/Cav is slightly less room, and the left (driver) sub was in the way.