X1997J

On my way to work today I noticed my jeep wouldn't shift into its final gear and sure enough half way through my commute the CEL came on and is reading code P0740. On my code reader the description is "Torque Converter Clutch Circuit Open". Does anyone have a good guess what this is? Runs great other than that.

2003 Grand Cherokee 4.7, Thanks.

dave1123

There is a solenoid pack inside the transmission that has the overdrive solenoid and the torque converter clutch solenoid together with the temperature thermistor on it. It sounds like the TCC solenoid coil is either burnt out or has a loose connection. When the TCC is engaged, it eliminates the slip of the converter and reduces the engine rpm by about 200 rpm. I've been driving mine for 5 years without the clutch because the problem is inside the converter and I'm not tearing it apart just for that. I still got 26 mpg on a 300 mile trip on the highway. What do I care if the engine runs at 1900 or 2100 at 65 mph?

X1997J

Damn 26mpg? Thats great, I only get 16mpg and before the tranny issue I was getting around 18mpg. The other weird thing is yesterday when I pulled into my parking spot the cooling fan (hydraulic) was turning really fast but the engine temp was at normal temp. I'll have to get in there and check that solenoid pack. Thanks.

dave1123

That's the only time I get that kind of mileage though. At a constant 70 mph over flat ground with a mild breeze. Normal in city casual driving is around 16 on a good day and 14 with stop&go. Also, I don't run my A/C because it hasn't worked in 6 years. I also had all the windows down. About your fan. Did you have the A/C on? That's normal for the fan to run on high speed if the A/C compressor is running.

I have to explain that mileage was on a trip between Syracuse and Rochester and back to Syracuse on a 90*F day with only a light breeze. That part of the New York State Thruway follows the State Barge Canal thru Montezuma Swamp National Wildlife Sanctuary and is about the flattest terrain you're going to find in this state. That is also direct calculation by fill-up, reset trip odometer, drive, wait one hour and return, fill-up at the same pump, divide mileage by gallonage pumped. About as accurate as you can get. The VIC said 27.7. Actual calculation was 26.4.

X1997J

I guess that makes more sense about you gas mileage. I always run my AC, I've never heard the fan that loud. IDK I'm pretty much over this POS WJ. I'll never buy another one. My XJs are solid and super easy to work on. I may try a ZJ one of these days haha. Thanks again.

dave1123

Yeah, my 2000 is complicated enough for me, but being a 4.0, it's pretty rugged. When she gets rusted enough that I can't repair her, I'm buying an older ZJ or XJ myself. OR another 99-00 4.0 WJ from out west or someplace they don't use salt on the roads.

X1997J

I know this post is old but I'm still having problems. Is there a way to test the solenoid pack without pulling it from the tranny?
Also when I'm going about 65mph on the freeway and let off the gas pedal it will shift into the last gear but as soon as I accelerate or go up a hill the rpms go backup instantly. Torque converter?
Should I change tranny fluid and add some kind of additive?
Thanks.

Damo

X1997J

Is your CEL on? I'm just wondering if CEL will come on if it is the actual torque converter vs the solenoid pack.
Thanks.

Damo