'96 Grand Caravan ESTransmission Problem

Hello,

I have a ’96 Grand Caravan ES and thought that the transmission was gone.
It was low on transmission fluid which I filled back to the appropriate mark. Started driving the van and it shifted through lower gears but it didn’t want to upshift into final gear, would run but had high rpm’s (slipping?). Drove it two miles home and parked. That evening let the van run for 20 minutes before rechecking fluids and a test drive. Still had high RPM’s and not shifting into final gear and kick/thump.

Vehicle has sat for one week. Did the key dance and there were no codes and no MIL. Purchased an OBDII reader. Two codes are displaying:

P0731 – Gear 1 incorrect ratio
P1782 – Pressure switch circuit 2-4

Did not erase the codes.

Test drove it today for about three miles. Shifted normally, ran great and I was feeling pretty good. On the way back, stopped at red light, idling in drive with foot on brake, the transmission kicked/thumped. High RPM’s started again, even at lower gears. Pulled over, turned off van, restart and again kick/thump. Did not recheck OBDII for new codes.

Van has 90,000 miles.
3.8L V6, 4 speed automatic transmission (PRND3L).
Last filter and transmission service was approximately three years/25,000 miles ago and I don’t know what type of fluid the transmission shop used. There was before and still is transmission fluid leaking. The transmission shop said the leak wasn’t from the transmission, so it gets fresh ATF+3 and now ATF+4 periodically.
Speedometer has not stopped.

Have not done any further diagnostic checking or part replacements.

Is this electrical?
Is this considered the “limp mode” or something else?
What is the kick/thump?
New filter and fluid (ATf+4)? And should the torque convertor be drained? If so, about how many quarts?
Input/output speed senors? How can they be checked?
Solenoid pack?
What indicates if you need a transmission control module reset/calibrated/learn? Can I do this or only a shop/dealer?
Can the instrument cluster cause this problem?

All replies and suggestions would be most appreciated. Thanks.

If the code reader will not clear the codes it sounds like an electrical glitch. Failure of the solenoid pack is not uncommon. If youf find a GOOD transmission shop they may offer to switch the solenoid pack and if it fixes it you pay them if not they will put the old one back on.

My bet is the solenoid pack.

Thanks Vats for the reply.

Update: this past weekend changed the fluid and new filter with MOPAR ATF+4. Fluid was very dark and some sludge in the pan. Probably the original filter. To make sure all fluid is good, planning on "flushing the torque converter/transmission via the removal of return trans cooler line into a bucket and refill via dipstick. Would it be easier to take the line off the radiator or off the front of the transmission? Which one is the return line?

Used code reader to clear the two codes. Test drove. Shifted normal until about three miles down the road. High RPM's about 40mpg. Only P1782 pressure switch circuit 2-4 code has reappeared.

Went ahead and changed the input speed sensor since the vehicle is apart. No metal particles attached to the sensor. Yeah! There is a small amount/trace of transmission fluid inside the sensor connector housing where the two pins are. How/what would you use to clean or dry the speed sensor or the connector wire piece? Would that apply to all of them?

Could the solenoid pack be removed and the gasket area cleaned then reinstalled to see if it makes any difference?

Have found solenoid packs by MOPAR, Borg Warner, ADT or ATP and others. The prices range from $85 - $250. Some says they are "updated" for Chrysler. Is that referring to a software version? Are the products and housing comparable qualities? Seems like they all have different stock numbers. Are there multiple solenoids for the 41TE?

Grateful for all comments and suggestions. Thanks.

Thanks Vats for the reply.

Update: this past weekend changed the fluid and new filter with MOPAR ATF+4. Fluid was very dark and some sludge in the pan. Probably the original filter. To make sure all fluid is good, planning on "flushing the torque converter/transmission via the removal of return trans cooler line into a bucket and refill via dipstick. Would it be easier to take the line off the radiator or off the front of the transmission? Which one is the return line?

Used code reader to clear the two codes. Test drove. Shifted normal until about three miles down the road. High RPM's about 40mpg. Only P1782 pressure switch circuit 2-4 code has reappeared.

Went ahead and changed the input speed sensor since the vehicle is apart. No metal particles attached to the sensor. Yeah! There is a small amount/trace of transmission fluid inside the sensor connector housing where the two pins are. How/what would you use to clean or dry the speed sensor or the connector wire piece? Would that apply to all of them?

Could the solenoid pack be removed and the gasket area cleaned then reinstalled to see if it makes any difference?

Have found solenoid packs by MOPAR, Borg Warner, ADT or ATP and others. The prices range from $85 - $250. Some says they are "updated" for Chrysler. Is that referring to a software version? Are the products and housing comparable qualities? Seems like they all have different stock numbers. Are there multiple solenoids for the 41TE?

Grateful for all comments and suggestions. Thanks.

I would try a electronic contact cleaner, you can get it in a can that is pressurized like WD40 and such.

Also check the electrical connector on the solenoid pack they a known for having moisture in them that can affect the signal from the Transmission Control Module. Do the same with it, clean it with contact cleaner. Actually check all connectors to tranny.

To drain all fluid remove the transmission line at the tranny and get a hose the same size about 4 feet long so you can put hose in a gallon milk carton to estimate how much you remove at a time. The line closest to the drivers tire should be the return line.

Hope this helps

Got the electrical cleaner for the connectors. I had replaced the input speed sensor as a precaution since the vehicle was apart. I just saw a TSB link that the new input/output speed sensors may require a new electrical connector or give possible dtc codes. Considering putting the old sensor back in since that wasn't a problem and no metal flakes were attached. Here's where I'm stuck now:Purchased a new Borg Warner solenoid pack with gasket. Have been reading that with the new "updated" solenoid pack, you remove and discard the metal separator plate and that the new ones aren't made to work with the plate. Original setup was solenoid, gasket, metal separator plate, gasket then on the transmission case just below the input speed sensor. The original solenoid pack has three metal dowels protrouding out the bottom which fit onto the metal separator plate. The bolts dropped through the solenoid pack, then the metal plate to secure it to the transmission case.The new solenoid pack also has the same three metal dowels for the bolts. The new solenoid will not fit and secure to the transmission case without the metal separator plate. It appears that on the transmission case, metal dowels for bolts 1 and 2 (passenger and center) will fit into their respective hole diameters but the hole where metal dowel for bolt 3 (driver) is a smaller diameter and will not allow the dowel to recess.I found a few pictures of new solenoids with only two metal dowels in positions 1 and 2. Does metal dowel #3 need to be removed to fit properly and bolt down? If so, how is best to remove the metal dowel?If not, has anyone installed a new "updated" solenoid with three metal dowels and the metal separator plate or some other method? Would it impair the working/design of the new solenoid?I really need to get my van running. Thanks.

Update:

Got the solenoid installed today. Have done a few test drives and so far the P1782 code is gone. Put the new input speed sensor back in. The van sure is quieter.