Ok, replaced the TCU with a rebuilt one. Install it and it's backing up now and has D-3, but odd still is missing d-4.


now... I notice my transmission fluid is reading past the "full" line. And I haven't added any transmission fluid and the last time I checked the level April 30th or so, the level was fine. How does a transmission get "over full" when no new fluid has been added? Also, now that is seems overfull, it made a grinding nose for 2 seconds and then the sound went away. But when the vehicle got warm or hot, didn't seem to want to shift correctly and at high RPMs. Any thoughts?




Thanks,
Michelle

 

If the car has been sitting for a while the ATF in the circuits may bleed down into the sump. Start the car, charge every gear for a few seconds, place it back into park, pull the dipstick, wipe it, reinsert, pull it out and check. You may find that the sump has now gone down.

Why was the TCU replaced?
Does your D4 light work? This is the best way to get codes from the TCU.

If you are having upshift issues 1>4 with grinding, check the right side cover NM/NC sensors for buildup, check their resistance values, and check the wire harness.

If you are having downshift issues check the VSS.

 

I do not have the D-4 light. I replaced the TCU because when I actually opened it up it had burned/fouled resistors and capacitors. It's just something I did when I had the "s" light lit and no D-4 gear. (limp mode)

My car actually drives short distances all gears EXCEPT D-4 and then when it gets hot...then I'll lose gears. (It's frustrating)


#1: Both the NM and NC sensors have buildup around them, what does that mean?

#2: Does the wire harness have a name?

#3: A VSS is so inexpensive, it seems best just to replace.

 

Keep in mind that atf fluid will rise as the car warms up. There is a cold mark AND a warm mark above it.

You may not have realized it was normal for that to occur and you may have originally had too much atf fluid to begin with.