Second Rebuilt Transmission Issue

[bjordan]

I have a 1998 Ram 1500, 2 wheel drive, 5.9L that I have had since new. A few months ago, I thought the (original) but rebuilt tranmission (from a year ago) was "slipping". I ordered in a rebuilt transmission from Streetwise Transmissions and after about 3 months, it began "slipping/surging". My mechanic worked with their tech guy and they sent another transmission under warrenty 2 weeks ago. My mechanic installed it and I drove it 100 miles on the highway with any issues. I got gas and when I left the station, going up a light hill and merging into traffic noticed it was doing the same thing. I drove it home the next day and about 75 miles into the trip back, it really began acting up. What we have decided is that it is something outside the transmission, likely electrical. What is happening is the torque converter is disengaging and rengaging, at about 55 miles an hour and 1500-1800 rpms if accelerating. I have read it may be the alternator, which was replaced about 6 years ago and is a crappy one from AutoZone. The issue is very erratic and intermittent. My mechanic drove the truck this morning and it did the same issue after a few mines. He then disconnected the red cable at the alternator and drove it a while and it did not "slip". He reattached the red cable to the alternator and drove it another 15-20 miles and it did not "slip".

Has this happened to anyone before? What would be the course of trying to figure this issue out and make my truck reliable again. Are there other items to check outside the transmission. The truck is 100% stock. No wires have been cut or spliced, etc.

Thanks for the help!

 

[Fast69Mopar]

I have a 1998 Ram 1500, 2 wheel drive, 5.9L that I have had since new. A few months ago, I thought the (original) but rebuilt tranmission (from a year ago) was "slipping". I ordered in a rebuilt transmission from Streetwise Transmissions and after about 3 months, it began "slipping/surging". My mechanic worked with their tech guy and they sent another transmission under warrenty 2 weeks ago. My mechanic installed it and I drove it 100 miles on the highway with any issues. I got gas and when I left the station, going up a light hill and merging into traffic noticed it was doing the same thing. I drove it home the next day and about 75 miles into the trip back, it really began acting up. What we have decided is that it is something outside the transmission, likely electrical. What is happening is the torque converter is disengaging and rengaging, at about 55 miles an hour and 1500-1800 rpms if accelerating. I have read it may be the alternator, which was replaced about 6 years ago and is a crappy one from AutoZone. The issue is very erratic and intermittent. My mechanic drove the truck this morning and it did the same issue after a few mines. He then disconnected the red cable at the alternator and drove it a while and it did not "slip". He reattached the red cable to the alternator and drove it another 15-20 miles and it did not "slip".

Has this happened to anyone before? What would be the course of trying to figure this issue out and make my truck reliable again. Are there other items to check outside the transmission. The truck is 100% stock. No wires have been cut or spliced, etc.

Thanks for the help!

A failed or poor quality diode in a cheap alternator can introduce a ton of electrical noise into the vehicles electrical system. This interference can cause stable voltages to become erratic like the voltage on the TPS or the TCC/OD Solenoid circuits.

Using your scan tool monitor the voltage to the TPS while the slipping is occuring and see if the TPS voltage is constant and stable or erratic. Also, monitor the voltage on the TCC/OD solenoids and watch the converter clutch to see if it is constantly engaging and disengaging.

 

[bjordan]

A failed or poor quality diode in a cheap alternator can introduce a ton of electrical noise into the vehicles electrical system. This interference can cause stable voltages to become erratic like the voltage on the TPS or the TCC/OD Solenoid circuits.

Using your scan tool monitor the voltage to the TPS while the slipping is occuring and see if the TPS voltage is constant and stable or erratic. Also, monitor the voltage on the TCC/OD solenoids and watch the converter clutch to see if it is constantly engaging and disengaging.

Thank you!

I have forwarded this to my mechanic. If there are other suggestions, please add them!

 

[Yeret]

What is happening is the torque converter is disengaging and rengaging, at about 55 miles an hour and 1500-1800 rpms if accelerating.

I've had a similar thing happen before. It turned out to be a faulty throttle position sensor. While cruising on the highway in OD, anytime I'd hit a bump, the torque converter would briefly unlock, then lock back up. Also during this time, the engine would occasionally idle very high for seemingly no particular reason.

While using a live-data scanner, I noticed occasional, erratic readings from the TPS, which also coincided with the engine running a high-idle. I replaced the TPS, and both problems disappeared.

 

[Evan02]

Actually anything eletrical can and will affect these transmissions in a negative way.
Bad grounds, dirty noisy alternator, ****** battery cables clamped on ****** terminals even connections on starter.

All battery cable connections need to be shiny metal to metal not dull grey or coated in green goo growing.

Dull grey is film that forms looks ok but is not a good connection.

Need to fix all these issues tgat most all these old trucks have before even attempting to diagnose a auto trans problem.
Id check to see fluid is in its then go to electrical first.

Good luck id suspect if your mechanic doesnt know this that you might also consider finding a new shop or even a good mechanic working out of there garage.