We have a 3.3L Grand Voyager with transmission issues. The van does not move at all, none of the gears work. However when shifting through the gears you do hear some movement going on, sounding like it is shifting the metal gears, however it does not move. The gear selector indicator also changes showing which gear you are in.

We have changed the tran oil, solenoid, speed sensors, tcm, and removed and cleaned the ground wire.

When we loosen the tcm bolt and pull it away (basically disconnecting it) the gear selector indicator on the dash lights up all of the gears however when put in drive the car does move. I took it out for a spin (noticed the speedometer did not work when the tcm is also pulled) like that and it stayed in 1st gear, it did not change gears at all. However when the tcm is pushed back into place and the gear selector lights up showing the correct gear selection the van does not move.

I am not sure what the problem is, I have looked through the forum however can't find a solution, I know my transmission is not the issue since first gear worked just fine.

 

The gearstick selects 2nd, R, D, N and Park. The other gears are selected by the TCM or EAXT for diesels.

If with the TCM pulled you get 2nd gear then at least some of the mechanical parts of the gearbox are OK. You will need to get the fault codes read to diagnose the electrical side of the gearbox and TCM. Without proper diagnosis you will just be wasting money throwing parts at it.

Regards
Richard

 

The transmission did not shift when the TCM was pulled, so I am not sure if it was in 1st or 2nd but it did not shift even when driven close to red line.

I wish a code would pop up so then I would be able to scan it, however I cannot get a code to come up. I drove it with the TCM out wishing a code would come up but nothing, so I assumed no code would show up since the TCM was not connected and hence it would not be able to send the ECM any codes.

Anyway I can get a code to show up?

 

When you say looking for a code to pop up, are you just doing the key dance to check for stored codes?
I think transmission are advanced codes that you'd need a proper reader to pull up unfortunately.

 

I have a matco scan tool which reads transmission codes, abs, airbag along with the standard codes. So as long as the TCM sends a code to have the Check Engine light pop up I should be able to read what the actual transmission code is.

 

with the TCM pulled the PCM will raise a code saying that it can't speak to the TCM, or at least your scan tool will raise an error that it can't talk to the TCM.

I can't think of a situation where you have the TCM out and no fault code is raised.

Regards
Richard

 

I'll try to remove the TCM and run the car with the scan tool in place to see if I get anything. Ill see what happens when I try again today.

 

Removed the TCM and ran the car but no codes showed up.
Only noticed that the van can be in neutral, and when shifting to D, or 3 or L, a hard transmission shift happen. However each of those gears work. Only gear that did not work was reverse. Note that again once the TCM was removed, the speedometer did not read and the gear selector indicator lighted up all the gears.

 

So after messing around with the TCM, it looks like I got a P1768 code. I looked at the TCM relay and it seems to work.

What else can the P1768 code mean?

 

that is supposed to be raised when the there is a problem with the TCM, or it could be the relay/wiring energizing it or the contacts being monitored.

Regards
Richard