moderate Z28

What can make your torque convertor not lock up? I have a 93 Trans Am with a non electronic 4l60 and 3.23 gears and the convertor hasnt locked up since Ive had it. I can hear it go through all 4 gears and then it never locks up. I was running about 2500 rpm's at 80mph. What could cause this?

Ragtop 99

iTrader: (7)

You should be turning about 2400 rpm at 80 mph. Maybe you don't feel the lock-up, but your rpms are with the error of margin for your speedo/tach. Do your rpms vary much by the amount of throttle input?

jimmyblue

iTrader: (11)

My 3.23 car turned 2500 (per tach) at 80MPH locked up.
I think you are locked and not noticing it; perhaps it locks
through the shifts, or perhaps it applies at the same time
as the shift at low throttle.

moderate Z28

Maybe it is but isnt it supposed to unlock when you press the brake because I dont feel that either. I'm just not seeing the rpm's drop . Shouldnt it jump up when I press the brake and go back down in rpm when I let off the brake? Thanks!

jimmyblue

iTrader: (11)

It should unlock if it's electronically controlled, but you
indicated it's not (?). If you keep one foot on the gas
and one on the brake the RPM should jump up as it
unlocks. But, maybe the 700R4 has a different scheme.

All I know it, unlocked my cruise RPM was well higher
than 2500. Though a stock converter will hold down
tighter than my current 3000. You should still see some
RPM rise with throttle, unlocked while if locked it should
rise hardly at all (though some slip may be seen).

moderate Z28

Yeah they dont jump up like they should. I've only had the car a few months. Do you think someone could have done something wrong? Maybe Ill try to drive it some more and see if I'm missing something.

lt1dave

iTrader: (7)

Most likely the lock up sol.. Scan it and make sure its sending signal from the pcm, if it is, drop the pan and replace the sol. Its an easy and cheap part to replace and a very common failure.

SmokingWS6

iTrader: (1)

Should be opposite of that. A loose will drop to 1200 rpm or so when applying the brakes at highway speed. stock programming unlocks the converter when you apply the brakes. This should be the same with the 700r4

Its simple to test if its locking up. at curising speeds it should feel similar to manual at light throttle changes. If you give it slightly more gas or coast the rpm should not change if its locked up.

Smitty

The rpms sound close.Have you had the car long?Some times people will wire the TCC to lockup/apply by wiring it into the 4th gear pressure switch.Usually this is done if the pcm takes crap and wont do it on it's own or in street rod applications.Does the 3/4 shift seem to be a lil firm or funky?

moderate Z28

Thanks for all the replys! The rpm's rise steadily when I give it gas. The 3-4 shift feels right to me. Ive been told I need to check the TCC. Can anyone tell me exactly where it is? I havent had the car too long I just took my first trip in it and me and my brother noticed it. Hes had a bunch of 700-R4's in his cars.

1jfuddle

iTrader: (7)

The best way to check the TCC is on the outside of the converter. There is a reason converters are painted bright, pretty colors. On the flat side on the back of the converter, look for a burnt section of the paint. That flat section is where the clutch is, and if the clutch is burnt, it will burn the paint.