[phinxter]

04 WJ with a 4.7. We have had some around 0 deg F temps here. I am aware of these Jeeps have a elaborate shift schedule depending on the outside temps and the TC will not lock up until a certain temp is reached. Yesterday it was around 2 deg, and I drove about 15 miles with no OD on the hwy. I pulled into a rest area, shut it down and restarted, took off down the road again and all was fine. I have seen this mentioned all over the internet but have never seen a solution, except maybe replacing the thermostat which seems ridiculous since it's blowing heat in 5-7 minutes. Anybody know of anything? I also read a trans temp sensor might be at fault but still never found any mention of if that fixed it or not.

 

[MoparNorm]

A thermostat will not help, because it's the trans temperature, not the engine temperature.
Likely what happened is that your stop and start (turned the key off) reset the computer.
That could likely happen if you pulled over at 5 miles, in lieu of 15.
At 2 degrees, I don't work well either.

 

[Bob Lincoln]

Could be the transmission fluid temp sensor has a loose connection. But my truck has a hydraulically controlled transmission (except for the electric overdrive), and this problem has happened to me. Mine depends on coolant temperature, but starting in 1993 it's transmission temperature that the computer uses to decide to lockup. In my case, I find that if the truck has been sitting a few weeks or more it can misbehave this way, and shutting down and restarting fixes it for me, too. I suspect a fluid change might make it happen less often.

 

[dana44]

A trick I have recommended and done myself for many years is to take a piece of cardboard and place it on the front side of the radiator to cover the bottom fifty percent. I will help the engine and everything warm up but with temps below 45 degrees will in no way damage anything, When you get into freezing temps, well, just that much more reason to do it automatically and is probably helpful in getting the temp up where it belongs and start circulating faster, prevent the old frozen/heating up too much in the engine only syndrome.

 

[ImperialCrown]

Schedule

Condition

Expected Operation


Extreme Cold

Oil temperature below -16° F

-Park, Reverse, Neutral and 1st and 3rd gear only in D position, 2nd gear only in Manual 2 or L


-No EMCC


Super Cold

Oil temperature between -12° F and 10° F

- Delayed 2-3 upshift


- Delayed 3-4 upshift


- Early 4-3 coastdown shift


- High speed 4-2, 3-2, 2-1 kickdown shifts are prevented


-Shifts at high throttle openings willl be early.


- No EMCC


Cold

Oil temperature between 10° F and 36° F

-Shift schedule is the same as Super Cold except that the 2-3 upshifts are not delayed.


Warm

Oil temperature between 40° F and 80° F

- Normal operation (upshift, kickdowns, and coastdowns)


- No EMCC




Oil temperature between 80° F and 240° F

- Normal operation (upshift, kickdowns, and coastdowns)


Hot

- Normal EMCC operation


Overheat

Oil temperature above 240° F or engine coolant temperature above 244° F

- Delayed 2-3 upshift


- Delayed 3-4 upshift


- 3rd gear FEMCC from 30-48 mph


- 3rd gear PEMCC above 35 mph


- Above 25 mph the torque converter will not unlock unless the throttle is closed or if a wide open throttle 2nd PEMCC to 1 kickdown is made