Hello All,

This weekend I dropped the transmission pan, replaced the filters, installed a transgo shift kit and sonnax line pressure booster.

Put everything back together, added 7 qts of ATF+4 and drove it for about 150 miles and all was well. Shifting was smooth but quick :-)

However, the very next morning (it was cold), I started it up and started to drive when the truck locked in 4th gear. Turning the truck off/on resolved the issue and it was fine for the rest of the day. This morning, same thing happened...locked in 4th...except this time when I went to stop, the engine stalled. Truck did this 2 more times, then it started working normally again.

The manual states to check the transmission fluid while hot (180 degrees F), however my transmission never gets above 125. Could low transmission fluid cause this type of behavior? What is the correct way to get an accurate reading if my transmission oil never gets that hot? For what it's worth, at 118 the fluid level was slightly above the two "add cold" holes.

Any suggestions will be greatly appreciated.

Thx,

Phil

 

Can't help you much except to say unless I am towing something real heavy my trans never gets up to 180. Most I have seen is about 150 or 160 even when towing. So with a cool/cold tranny, unmolested, I have never had any issues with shifting.......Yet!

 

sounds like transmission is going into limp mode
maybe try resetting pcm will clear up your problem

disconnect negative battery terminal
turn ignition to crank for few seconds
reconnect battery

 

Yes, it is definitely going into limp mode. What I can't figure out is why this only occurs after the truck has been sitting for a long period (overnight).

I'll try resetting the PCM to see if that helps.

Thx,

Phillip

 

Try taking off the line booster. It is the easiest thing to test first. Take it off when it is hot. Might be doing something wrong to the trans when it shuts off?

 

First are you sure the shift kit install/bolts are all torqued properly? Also I have been seeing this more recently at my dealership, trucks coming in stuck in 4th gear. I've been replacing the shift solenoids and has confirmed the fix for it being stuck in 4th gear.

 

ohhhhhhhhh boyyyyyyyyyyy, bet that trans kit will be comin back out.
Line booster...whyyyyyyyyy, they dont need it...!

Bye byeeeee lifetime drivetrain warranty...!

 

Hi All,

I just wanted to provide an update on my issue just in case some other soul runs into the same problem I did.

1.) I made sure the fluid level was set correctly based on the temperature vs. mm on the dipstick graph I found from the service manual. -- I was about 1/2 quart low.

2.) I removed the inline pressure booster and the "stuck in 4th" symptom appeared to go away. However, I was still noticing stalls (intermittent) when coming to stops or when switching from reverse to drive.

3.) I hooked up a code reader and came across a pending DTC P0868 (Line Pressure Low). Some of the possible causes are:

- LOW FLUID LEVEL
- (F856) 5-VOLT SUPPLY CIRCUIT OPEN
- POOR LINE PRESSURE SENSOR CONNECTION
- (F856) 5-VOLT SUPPLY CIRCUIT SHORT TO GROUND
- (F856) 5-VOLT SUPPLY CIRCUIT SHORT TO VOLTAGE
- (T118) LINE PRESSURE VARIABLE FORCE SOLENOID CONTROL CIRCUIT SHORT TO ANOTHER CIRCUIT
- INTERNAL TRANSMISSION
- LINE PRESSURE SENSOR
- CRACKED, PLUGGED, OR MIS-INSTALLED PRIMARY OIL FILTER
- LOOSE COOLER RETURN SPIN ON FILTER (IF EQUIPPED)
- STUCK OR STICKING MAIN REGULATOR VALVE
- POWERTRAIN CONTROL MODULE

I had already checked the fluid level and that was ok, however I noticed that there was some air bubbles on the dipstick indicating that air was in the system.

5.) Out of the above list, a cracked, plugged, or mis-installed oil filter would cause some air to get in the system, so it was time to drop the pan again.

6.) I dropped the pan and immediately noticed that the seal between the pump and filter was not seated properly. The sump filter literally fell out when I removed the one bolt. (Filters were bought from NAPA)

7.) Since I had the pan dropped, I removed the vavle body again and double checked that the shift kit was installed properly - I didn't find anything here. Put it back together and back into the tranny it went.

8.) I bought new filters from MOPAR, ensured the seal was seated properly and installed both filters.

9.) Put the pan back on and filled it up with 6 quarts of ATF+4. Started engine to allow tranny temps to come to normal operating temp..then slowly added about 1 qt of ATF+4 until the level line on the dip stick was good.

10.) Test drove last night and again this morning and thus far all of my symptoms have disappeared.

I would highly suggest that anybody who is servicing their transmission, buy MOPAR filters and save yourself the hassle and money (in fluid).

I installed the shift kit to improve performance and longevity of the transmission as I tow a lot. If I start to have real problems with my transmission...its not that difficult to drop the pan and put the stock springs and cover plate on :-)

In any case, I hope my problem/symptom can be useful to somebody else if they are unfortunate to be in my position!

-Phillip

 

Nice. Did you wind up putting the line booster harness back in?

 

No, I didn't want to introduce extra variables during the troubleshooting. I'm still debating on putting it back or selling it.