Author: Dan Frazier
Subject Matter: Diagnosis
Vehicle Application: 1995 Ford Ranger 2WD
Issue: TCC stuck off
For those of us who have spent a fair amount of time in a shop, you have to wonder whether there would ever be a time when you could say, “I’ve seen it all.” It seems that every day we run into some variation of a problem that is just unusual enough that we have to start diagnosing from a clean sheet of paper. Although this scenario involved a mechanical issue, it was, well – different. Somehow these kinds of stories often seem to involve a previous repair performed by another shop, and this story is no different.
The vehicle was a 1995 Ford Ranger 2WD, equipped with a 4R44E transmission. It had originally been repaired by a local transmission shop that had removed the unit and rebuilt it in house, though we had no knowledge of what the original complaint was at the time. After their repair, it would set a P0741 (TCC stuck off), OD light flashing etc. They’d had the vehicle for quite some time but then decided to purchase a remanufactured unit from one of our distributors when repairing the rebuilt unit was unsuccessful. After installation of the remanufactured unit, the same code and symptoms returned. It was then that the vehicle was brought to our shop for diagnosis.
After verifying the concern and pulling codes, I did some basic tests to determine whether the PCM was commanding the TCC solenoid correctly, and to make sure the TCC solenoid was functioning properly. I found no problems with the solenoid, circuit or PCM command. While watching the TCC slip in the PID data while driving, you could see the TCC start to slip, and as soon as it hit 200 rpm the OD light began to flash. With this solid information I made the determination that it had to be an internal problem with the transmission. I would later discover that I was right – well, sort of.
We ordered a replacement unit from our plant. As we were completing the unit installation, my R&R tech discovered a couple of extra washers lying on the frame rail. We looked at all the bolts and couldn’t find anything missing, so we buttoned up the vehicle and proceeded to start the engine.
Upon startup, my ears were treated to the familiar and troublesome “screech” of a starter drive still engaged. I looked up through the inspection cover and the starter drive was hitting the flex plate. That’s when the R&R technician said that, during the installation, it seemed as if the converter had to pull away from the transmission much farther than usual to mate up with the flex plate. That’s when the red flags began to show themselves. Now we had something to look at.
We pulled the starter out to make sure that the drive gear wasn’t seized or sticking, and it wasn’t. After some pondering and a closer look, we determined that the extra washers were being used as starter shims between the starter and transmission. Those of you who know Fords also know that they don’t use starter shims from the factory at all.
What we think happened was that the first R&R technician didn’t have the converter studs lined up when he mated the in-house rebuild to the engine, zipped the bellhousing bolts down with his 1/2-inch impact wrench and inadvertently bent the flex plate in. This caused the sealing ring for the TCC oil supply to barely seal on the torque converter (because the converter was being pulled an excessive distance away from the transmission), letting the TCC lose pressure. That also explained why none of the other units functioned properly, either.
We ordered a new flex plate for the vehicle, and when the new part was compared with the flexplate that we had removed from the vehicle, we found that it was almost 1/2 inch taller. After the installation was completed with the new flex plate, we performed a few road tests to ensure that the issues were completely resolved. No lights came on during the road tests, and no codes were set. The vehicle was released to a smiling customer.
We’ll never know exactly what caused the bent flex plate in the first place, as it is possible that an incorrect, used flex plate was installed because of ring-gear wear. Or the original technician simply made an installation error. Who knows? It just goes to show that anyone can make mistakes, and some of them are just harder to find than others. The phantom washers were the giveaway in our situation, but sometimes the clues aren’t so obvious. Just when you’ve thought you’ve seen it all, know that you never will, at least not in the repair business.
Dan Frazier is a diagnostician at Certified Transmission’s retail location in Grandview, Mo. An ASE certified master technician, he has been in the automotive industry more than 30 years.