47RE is hunting for gears now...wtf?

[flubyux2]

well after replacing my pressure transducer and governor solenoid, filter, and fluid, the truck ran great for a while. itd get out of the hole nicely and have positive upshifts and tc lockup. but after fixing one problem, i get another.

it now hunts for gears and the converter solenoid cycles on and off. so cruising down the freeway, the converter will unlock and lock back up, sometimes repeatedly, maybe 10 times within 30 seconds.

then, sometimes, w/o changing throttle position, it downshifts into 3rd and wont upshift. it stays in 3rd gear, doesnt lock up and does 50mph at about 2200.

and when it gets REALLY bad, ill take off from a stop in 1st gear and itll TRY to go into 2nd, but hunt back and forth before surging into the next gear. then itll do it again between 2nd and 3rd. it wont go into 4th gear though.

ive put the scan tool on there an watched the TC solenoid cycle on and off. my TPS voltage didnt spike though. neither did my trans temp or trans temp sensor voltage. my TPS doesnt seem to have any flat spots as i open and close the throttle when i watch it on the scanner.

the problem only seems to show up at night time. its usually problem free during the day. some people say its the alternator creating alot of electrical noise because of worn brushes? everyone says this is usually the cause of problems on the 24v trucks w/ the APPS. i saw a TSB for a hunting problem that pertained to the TC unlocking and locking, but im having problems w/ 2nd,3rd and 4th engagment too.

[Dano Moparo]

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.

[Dano Moparo]

And another

[flubyux2]

thanks dano. i keep hearing that bad brushes in my alternator could be the cause of my shifting/TC lockup issues. that TSB sounds like it could be what i need... i guess thats the nitty gritty of what a reflash really is?

i know my problem MUST be electrical in nature. when the problem isnt occuring, the tranny shifts flawlessly and locks up w/o issue. so im lead to beleive my tranny is mechanically sound.

have you heard of adding an RF choke to certain engine harness wires or noise sheilding like aluminum foil or braided jacketing to the TPS wires? maybe to the alternator power cables inside the harness?

thanks a bunch

[Dano Moparo]

have you heard of adding an RF choke to certain engine harness wires or noise sheilding like aluminum foil or braided jacketing to the TPS wires? maybe to the alternator power cables inside the harness?

thanks a bunch

I've never heard of anyone trying that. I'd give it a try, cant hurt.