I have always wondered if mine was operating properly, and now that I have my car going into closed loop, I'm thinking it isn't. I'm only getting about 15-16 mpg, almost all highway driving. What happens when it locks up? Does it behave almost like a manual in gear i.e let off gas, it will engine break, give it gas, car speeds up before RPM? I get that in 2nd and 3rd, but when I put the car in OD, I dont get that feeling on the highway. If I do find out it isnt working, would a switch be a viable option, and what is the easiest way to run one?

 

Revs should drop 2-300 rpm when lockup engages and rise the same when you touch the brake pedal to unlock

 

Lock up feels a lot more direct at highway speeds. It's just like driving a manual transmission. There is zero mush between accelerating faster and the RPM's rising. With the converter unlocked, there is a small bit of mush (extra RPM rise) and it's easier to accelerate.

Stock lockup occurs at 25 mph or 40 mph depending on model. L98's for example lock at 40 mph. When it switches to lockup mode, it will feel like about 1/2 a gear difference.

 

It's been a while since I was aware of the TCC locking and unlocking.

Try this No. 1:
1. Put the trans in manual 2nd and accelerate from a full stop.
2. You'll feel it shift = 2nd gear
3. You'll then feel another "light bump" = indicates TCC lockup with a slight drop in RPM

Try this No. 2:
1. Drive the car in OD or D at a steady +65MPH
2. Take foot off gas pedal and coast for a sec - note RPM's
3. Tap brake pedal. The TCC should unlock and the PRM's should drop.

 

Thanks for the replies, guys. Looks like I have another circuit to repair. Do the solenoids really go bad or is it usually a wiring issue? I feel like it may be hunting when in 2nd. If I keep a steady pressure on the throttle at around 35-40 if feels like it eithre continuously locks and unlocks or just surges slightly/hunts. In D or OD i get not RPM change on the highway after doing what was suggested above.

Edit: Just for reference, I do have an aftermarket tach hooked up because mine has the resistor problem and is constantly pegged completely around the gauge, so I should be getting pretty accurate RPM readings.