Tc lockup problems. Stays locked through full rpm in 3rd & 4th

[CherryK5]

My TC lockup is locking up all the way through 3rd and 4th. i just drove down the road at 40mph and 1000 rpm... What gives? the only thing ive done is replace my radio fuse. and dick around with my electric fans. neither of which are in the same electrical circuit as the lockup.

Edit: i tried my hand at searching but couldnt find much. most of it was "my tc lockup wont lock up"

 

[Fordum]

Unless you have a short that is keeping power to the lockup circuit all the time, sounds like you have a frozen bearing in the torque converter.

I finally had to read this thread.
I skimmed the title several times finally decided to see how the transfer case was staying locked in 3ard and 4th......

 

[Blue85]

No, the TCC can't be stuck or you couldn't bring the vehicle to a stop with taking it out of gear or stalling the engine. There is a trick that old-timers use when they can't figure out the wiring. They put a check ball inside the solenoid so it acts like it's always on - giving lockup through 3rd and 4th. The pressure for lockup comes from a valve, so there is no pressure available to lock the clutch in lower gears. The solenoid normally vents this pressure back to the pan when there is no current through it. You may have some junk stuck in the solenoid. You can pull it out and check it just by dropping the pan.

 

[CherryK5]

No, the TCC can't be stuck or you couldn't bring the vehicle to a stop with taking it out of gear or stalling the engine. There is a trick that old-timers use when they can't figure out the wiring. They put a check ball inside the solenoid so it acts like it's always on - giving lockup through 3rd and 4th. The pressure for lockup comes from a valve, so there is no pressure available to lock the clutch in lower gears. The solenoid normally vents this pressure back to the pan when there is no current through it. You may have some junk stuck in the solenoid. You can pull it out and check it just by dropping the pan.

I'll check it out this week then. i just unplugged it. runs the same, maybe it wasnt locking up in the first place

 

[Blue85]

If the brake pedal check doesn't work, you can test the lockup with cruise control. If you go up and down grades at the same speed, but the rpm changes, it's unlocked. Or if the rpm seems to change immediately with throttle changes instead of only with vehicle speed changes.