Well damn. The 'customer' also hasn't had any stalling issues, even when I pulled one of the transmission fuses/relays and it drove like I was towing a house. At this point, I wouldn't rule out some crazy short in the wiring somewhere in this process of signaling the torque converter to lock or unlock. Whether that's the brake pedal sensor, which is more unlikely since they are no longer separated into two brake light + cruise control and TCC plungers, or the TCC solenoid itself, I have no clue. I've yet to receive any transmission related codes in the life of the car, but I also received no codes for the 4 years my ABS module was busted, so call me crazy.Originally Posted by brettstoner
Went out for another test drive tonight with the Torque app comparing the PID for the TCC slip speed and the engine speed. As far as I understand:
- At a stop in gear, the slip speed should be almost exactly matching the engine speed with single digit variation at most.
- With normal city stop n' go driving or getting up to overdrive speeds, the slip speed should bounce around a few hundred RPMs below the engine speed
- In 4th/OD, when the torque converter is supposedly locked, the slip speed should be essentially locked at 0, although I've read in various places a variation of up to even a hundred or so RPMs above 0 is acceptable as something normal.
As for my results, it was very difficult to do this with my luck of traffic and having to pay attention to my poorly mounted cell phone with Torque running. I took two interesting shakey shots with my other phone which I'll just write out. I only took them once the numbers stayed roughly the same for at least 10 seconds while holding the throttle steady. I had a TCC slip of 17 RPM/engine 1414 RPM at 51mph and the other shot was (after doing a u-turn and going down the same flat road) was a TCC slip of -170 RPM/engine 1368 RPM at 52mph. Since I also read the TCC slip is a calculation of gear ratios compared to the engine speed, it can sometimes show up in a negative. But these seem like two wildly different numbers with only one mph difference. Otherwise, everything else matches up at a stop and slips normally when just driving around like grandma.
Unfortunately, I couldn't tell if the slip numbers did anything different when I would force the surging to happen under heavy loads/hard acceleration since I was too busy reining the car back in
Sorry for the long-winded technical posts. I'm just so desperate to find out what the hell has been plaguing this otherwise magnificently reliable vehicle for the past 8 years, even if I don't ever get to fix it. I'm starting to doubt the transmission at this point considering how long this has been going on without anything crazy breaking. Looking at other TCC solenoid problem posts, there's usually an element of hard shifting or stalling or some other issue that would make simple driving a pain. If you're just in the city and don't have to merge into traffic at a high rate of acceleration from a stop or run from the police, then you'd have no idea anything is wrong with the car.
