I found a couple different tsb's that may apply.

SUBJECT: Erratic Torque Converter Clutch (TCC) Operation (5.9L Diesel Applications)

DATE: Feb. 19, 1999

OVERVIEW:

This bulletin involves selectively erasing and reprogramming the Powertrain Control Module (PCM) with new software (calibration changes 98cal12 & 99cal14).
NOTE: THIS INFORMATION APPLIES TO VEHICLES EQUIPPED WITH A 5.9L 24 VALVE DIESEL ENGINE AND AUTOMATIC TRANSMISSION BUILT BETWEEN JAN. 1, 1998 AND DEC. 18, 1998 (MDH 0101XX & 1218XX).
SYMPTOM/CONDITION:

Some vehicles may experience a surge like condition while in 4th gear. This may be caused by the Torque Converter Clutch (TCC) unlocking and locking when it should be consistently locked. The cause of this erratic operation has been identified as electrical noise from the Throttle Position Sensor (TPS) or Alternator.
DIAGNOSIS:

Using the Mopar Diagnostic System (MDS/MDS2) and or the Diagnostic Scan Tool (DRB III®) with the appropriate Diagnostic Procedures Manual, verify all engine/transmission systems are functioning as designed. If Diagnostic Trouble Codes (DTC's) are present, record them on the repair order and repair as necessary before proceeding further with this bulletin.
Verify the condition by creating a custom display in the DRB III® and include the following: SENSORS (Output Shaft Speed, TPS Volts, Trans Temp Degree) & INPUTS/OUTPUTS (Brake Switch, Park/Neutral, ASD Relay Sense, Desired TC Clutch).
Drive the vehicle with a helper monitoring the DRB III®. Warm the engine and verify the transmission fluid temperature is greater than 32F and consistent. Operate the vehicle with an output shaft speed greater than 2200 rpm. Verify that the brake switch shows a released status that is consistent and verify the park/neutral status reads D/R and is consistent. While keeping the output shaft speed above 2200 rpm, hold the throttle so the TPS reads 1 volt. Monitor the TC clutch status, it should be consistently locked. If the TC clutch status shows unlocking/locking, look to see if the TPS volts are fluctuating by 0.2 volts or more. If the conditions are met, perform the Repair Procedure. If a surge like condition is felt but the above test does not confirm the TCC unlocking/locking occurrence, further diagnosis and testing will be required.