Are you sure that you have a converter clutch? If it's ever been rebuilt due to the infamous Chrysler converter clutch disintegrating and plugging the rest of the trans I doubt that any rebuilder replaced it with a lockup converter. When it went out on my Caravan I went to 4 rebuilders ..none of them typically, including some premier shops, replaced the converter with a lockup type. They appeared very leary of doing so.

Even without a converter clutch ..you're still at big block mileage levels.

The signal from the PCM (at least in the 99 model) to actuate the coverter clutch is through a 3 or 4 prong connector. The actual hydraulic soleniod appears to be an internal thing attached (via tubing) to the valve body. What I think you're refering to is the shifter cable ..which has a large intermediate body somewhere off of the trans.

If in fact this has not been rebuilt with a non-lockup converter .AND if the internal solenoid is defective ..it doesn't look like a labor intensive job.

 

The Jeep powertrain code (SAE) is P0740 (hex $94), No RPM drop at TCC lock-up. 9 times out of 10, the problem lies with an inoperative solenoid on the 32RE(TJ)/AW4(XJ)/42RE(ZJ) valve body. Most often an intermittent condition, and not the easiest to diagnose, especially w/o a DRB3 (or equiv).

Double check that trans fluid level, and make sure the TV cable is properly adjusted, with all other shifts clear and concise. If all else checks out, inside the pan is normally where the problem is. Not too hard a bill to swallow, even at a Dealership.

By the way, that solenoid on the shift cable is the Brake Shift Interlock, to prevent folks from pulling it into drive w/o their foot on the brake