Hi everybody. My dad's Caravan has the following problem.
He couldn't start the car in the morning because the transmission
went into R and stuck. We disconnected negative terminal,
tranny went into P and car started. It happened again but the
car didn't start. It flickered between Park & Reverse with weird
clicking coming from the dash area. We pulled the codes, there were
a couple:
P0720
P0700
P0732

We've owned the car since new. Transmission ran with no problems at all.
Really stuck in here
Can this be transmission control unit, ignition module, shifter?
Please help.
Sorry if this old thread, tried searching with no result.

 

If these are current codes and not history codes, i would look at that PO720 which is a problem in the output speed sensor circuit...That sensor is actually cheap and relatively easy to change....it is removed by a 1 inch socket or wrench and it is the one located nearest to the drivers side wheel on transmission case...Also when sensor is removed look for debri on end or it....Lots of debri means planetary failure.....



Brian

 

Like you physically can not move the shifter at all?

 

Something must of come apart inside trans to restrict the manual linkage......In that case, I would have someone to hold brake and the disconnect linkage on top of transmission ( it is relatively easy to do) and see if linkage will operate transmission....Those codes may be history codes and not relative here, but PO720 gets it signal from the rear planet which does explode from time to time..Is there any time in which the gear selector works and transmission shifts fine?

Brian

 

It's like, he came to a stop, shifted to park and turned off the car. Upon next start the shift is still in first position but the dash indicates/iluminates on reverse and we can't move it, nor start the car.

 

Ok, I take it that the shifter is functioning but the light stays illuminated the the R position....here is what i would do, go into the fuse box or distribution box under the hood if it has one and look for a fuse marked TRANS and remove it.....If trans is ok it will reverse with voltage removed from transmission, but will only have 2nd gear in the OD range......If no fuse is easily found, disconnect transmission wiring harness ( it is back with 8 wires/terminals)...But you must remove it with engine running because the neutral /safety switch is in that harness......( be sure and use caution)....I have an idea from your description that the lever position has failed...it is located inside transmission but is accessible through the transmission oil pan...

Brian

 

Gentlemen,

I've uploaded a video, hope this helps.
As you can see it won't go into Park at all and just skip over Neutral.
You can't hear it but there is a noticeable click when inserting the key.
Also CEL is flashing, I tried pulling the codes but there were none,
probably because the battery was disconnected.

Does this look like "neutral safety switch" problem, as bjr1a mentioned?

Thanks again for all your help!

http://www.youtube.com/watch?v=VmyBXzg8ScA

 

Ok, that does help some, apply emergency brake and open hood...may have to remove air cleaner ( its easy).....Now on top of trans you will see your shifter cable where it attaches to the transmission shift lever..Simply remove cable at the lever( its easy to do)....now the trans shift lever should have 6 positions by simply rotating the lever..If it does not, the problem is in trans...If you do have 6 easy to attain selector positions, then something has happened with cable or inside steering column.....

Brian

 

The transmission has 7 positions on the shifter shaft if the cable is disconnected. Only 6 are used with the shifter. The 7th click is for service work.

The problem looks electrical or a broken shifter shaft or a broken cable or something like that. Previous diagnostic procedures are valid, but I don't see why you need someone to hold the brake. Isn't that the purpose of the parking brake or a couple rocks/wood blocks.

I wouldn't waste my time messing with fuses. It would be best to start with the simplest stuff first like physically watching the shifter arm movement on the top of the trans. I "could" be a bad PRNDL or range switch.

 

ajhawk
Try removing the shift cable from the transmission lever. Turn the key on and with your foot on the brake,Move the shift lever inside the van. As bjr1a had said. If the shift lever moves thru all ranges, the cable is not the problem. Block the wheels and set the brake brakes and try moving the lever on the transmission. And post your findings.