I start the car, take it for a drive and I notice that lock up comes on in instantly in 2nd to the point it will try to stall the car if I do a rolling stop.

I rebuilt this trans. in the rebuild process I found out it was out of a caprice station wagon with a truck valve body non auxiliary. It was supposed to be an auxiliary valve body.

I put it together and tested it on a transmission Dyno. turning lock up on and off with a 12v power supply then installed it in the car and now this problem.

I think the problem is in the car not the transmission.

I know that when the car goes into second straight into lockup if i gas the pedal it will come out of lockup, then work fine.

Thanks
Alex

 

Bust out your DMM and probe the resistance on the top left and top right terminals. It should be open or over limit. Anything less indicates a short to ground in the TCC wiring that will lock the TCC in as low as second gear. Also check to make sure that the 4th gear switch is working properly (you'll need to pull the pan to test) using the same, but down under the car. If the trans has multiple gear position indicator switches, you'll need to make sure they all are open as above or the ECM may be getting a false signal.

It's either that or there may be a problem with the valve body...

 

we'll do I forgot to mention that this is on an 87 tpi 305 car

 

A 700R4 is a 700R4... Primary differences are in the number of clutch plates and the valve bodies (other than servos and stuff).

 

I'm not sure if I tested this right but I grounded to the case and tested each connection no short found. I tested the connection of the car and found that idling in park there was about 4 volts I'm not sure what that means.

Questions?
Where is the relay located for the tcc lockup
And does anyone have a good drivers side ttop seal I just tore mine

and what tells the car to go into lockup

 

There is no TCC relay. The ECM commands the lockup.

 

what tells the ecm to apply lockup? there is voltage in the plug. shouldn't there be no voltage?

 

There's always voltage in the plug when the brakes aren't applied, the ECM switches the ground. Nothing tells the ECM to apply lockup, it makes the decision based on sensor input.

 

ok what sensors tell the ecm to engage lockup something is not right car is engaging lockup all the time pretty much it will stall the car if you do a rolling stop

 

CTS, TPS, MAP, and VSS as far as I know... so pretty much all of them.

 

so what should we look at to make this car stop locking up

 

I'll take a guess,........ Converter, Maybe the Lock-Up solenoid in the tranny ?

 

Just on plug it and see how it run with out the harness hooked up

 

One thing that differs between 700r4's in different applications is whether the lockup switch(4th gear switch) used is N.O (normally open) or N.C. (normally closed). My car was a TBI car originally, which used the N.C. switch. When I converted it to TPI, I noticed most TPI 700r4's use the N.O. switch. If the polarity is wrong on that switch, it could be causing the ECM to be locking the converter when it's supposed to be commanding it to be unlocked. Since most Caprices were TBI, maybe the valve body in your replacement trans has the wrong lockup switch. If you still have your original trans you could grab the 4th gear switch off its valve body, drop the trans pan, and try changing that switch. Another good idea would be to put your original governor in the replacement trans. That Caprice governor is probably calibrated to shift the trans at a much lower RPM than a TPI trans. A factory shop manual or an ATSG 700r4 manual have diagrams in them that show whether your original application used a N.O. or N.C. lockup switch. Some applications also use a temp switch in the valve body to help control when lockup occurs, while other applications don't have the temp switch at all.