2007 Chrysler Pacifica Transmission Problem

TDBowes

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Vehicle: 2007 Chrysler Pacifica
Engine: 4. 0
Model: Touring, FWD Mileage - 190K
Problem Description:
When my wife came into a reststop after driving on the interstate for a couple of hours, the car stalled as she was parking. The engine would restart, but would stall and shut off if placed in Drive. She placed the shifter selector in Reverse, and the transmission worked fine. I had the car towed and made the following tests. The transmission computer had one code related to Torque Converter pressure high. I drove the car in reverse up a hill at my home, allowed it to coast in neutral to 3 mph and then shifted into Drive. The car drove normally until slowing to a stop, where upon it would stall the engine. Again, Reverse works fine. I pulled the drain pan and there are no metal particles and the fluid looks good and smells good. I have removed the valve body and solenoid pack and cleaned all meticulously and checked all solenoids for resistance and also powered all to check for pintle movement. After reassembly, the same problem persisted. For an additional test, I started the engine, removed the wiring harness connector at the transmission to force the transmission into a "Limp" mode. The problem still persisted, although worse. Reverse works fine. I am assuming that there is a broken component in the internals of the transmission? Any ideas before I remove the transmission from the car and begin disassembly? Any help/suggestion is appreciated! Tony
 

al daniels

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sounds like the torque converter is stuck in lockup.i would see if i could find the lockup solenoid and disconnect it to see if that alleviated the problem.
 

billr

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Adding to that: since the clutch will unlock in reverse, it seems that the TCC itself is OK and the hydraulic circuit for activating it is OK; i.e. the TCC solenoid is capable of effecting both lock and unlock, so it would be an electrical problem sending the TCC solenoid the wrong signal. For sure, disconnect it and let's confirm it's the TCC, then time to dig out electric schematics. Have you had a scan with a sophisticated (expensive) scanner, one that can read all codes?
 

jasonn20

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Getting the codes pulled and CVI's checked to see if within spec would be good idea. If there is no trans overtemp code then you more than likely do not have some parts welded together so the torque converter is probably coming apart putting some debris into the valvebody and other hydraulic circuits.
 

TDBowes

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Sorry it has taken me awhile to respond. I checked the Chrysler Service Manual (Book 4) and verified that the TCC soleonoid is mounted to the Solenoid Pack which is mounted to the valve body. When I disconect the wiring harness connector at the transmission, this removes the TCC solenoid from being activated by the transmission computer. Disconnecting the wiring harness connector forces the transmission into the "Limp" mode which forces the transmission into 3rd gear. In examining the manual, it appears that the only sensors or electronic devices that are not connected to the Transmission computer are the (1) The Input Shaft Speed Sensor; (2) The Transfer Shaft Speed Sensor; (3) Output Shaft Speed Sensor. All others are mounted on the Solenoid Pack/Valve Body.

I used an expensive Diagnostic Analyzer for reading the codes, Gensys (sp?) I borrowed it from a friend that works on school buses at their shop.

I am puzzled as to what can activate the Torque Converter Clutch lockup when no electric signal is being applied?
Tony
 

bp042665

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i have a shop and i had a simail problem and you might think im crazy but it was low fluid and cavitating have you checked the level with the proper tool ? not saying it is your problem but it did fix the one i had in my shop
 

billr

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Interesting... I always assumed hydraulic pressure engages the TCC, but that sounds like it releases it? Are they all that way, or does it vary with make/model?
 

bp042665

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i had a 2002 F250 do the same thing about a year ago and it was low too they never check the fluid level but thats my first check level and condition then so on from there but it need to be around 2 to 3 Qts low to cavitate also if it gets hot it will biol and lock up the converter
 

TDBowes

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I haven't accurately checked the fluid level, but I will. I purchased a dipstick from an EBay location for the Pacifica sometime ago. The Shop Manual shows the correct level for the dipstick based on fluid temperature, so I should be able to check it. I'll post what I find.
Thanks,
Tony
 

bp042665

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let me know what you find Tony if its not that ill do some more checking in my Books on that Tranny and my atsg books too
 

The old man

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Since it seems that you have diagrams of the valve body on this vehicle, look to find if there is a valve called "switching valve". If so, the switching valve is the main metering valve for controlling the torque converter. It works in conjunction with the lockup solonoid. A sticking switching valve can cause 2 different problems depending on were it sticks. If it sticks at the bottom of the bore you will get no TCC apply. If it sticks in the apply position, the vehicle will stall when coming to a stop. I would physically pull the switching valve spool out and make sure it is free in the bore. It may be sticking in the apply position.

Also like they said previously, make sure that you have enough fluid in the system so as not to enter air into the system and cause compression on the switching valve etc and cause tcc problems. Make sure you have the proper length dipstick since you bought it off ebay. If you thought it may be air in the system from the wrong dipstick, you can temporary ( and I do mean temporary), overfill it to elimate the possible air to see if makes a difference. Then you can suck or drain the excess out if that is not the problem. If it is the problem, get the proper length dipstick. Just my $.02 worth.
 

JackC

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Find a friend with the same trans or go to the dealer and find out if that dip stick is the correct length.
It's probably fine, but let's get that off our plate.
 

jonnblaze

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Have you had a scan with a sophisticated (expensive) scanner, one that can read all codes???
 

TDBowes

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I wasn't able to solve my problem. I had the codes scanned with an expensive scanner that could read and diagnose the Transmission codes as well. They were inconclusive. I received an email from a transmission shop that had experienced the same type of failure. They were able to resolve the customer's problem by changing the valve body. They suggested to purchase the OE valve body from Chrysler which is around $500.00+. I haven't gone this direction yet. I parked the car and purchased another car for my wife and plan to begin working on it next month. It seems like a "shot in the dark", but so far nothing else has worked. Somewhere in my email folders I have kept the email from the transmission shop. If I can locate it, I'll forward it to you.
 
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