I have a 87 trans am 350 stealth ram with a 92 4l60 700R4 and a 2700 rpm stall ACT converter purchased from Pro Built and the trans recently it lost the lock up function. The converter was purchased 3 years ago or so (12000 miles ago). I was just driving down the road tuning the ecm and stoped at a stop light and took off, I then noticed that I had no lock up. I checked the wiring going down to the trans and all is good (heck I even replaced the complete engine wiring harness) and still doesn't work. I then opened up the transmission pan and checked the lock up solnoid and it checked out ok, I had a spare wiring harness from another trans and replaced it and still doesn't work. Yesturday I put a volt meter to the wire coming from the computer to see if the computer is commanding the lock up and it is. I also checked the brake switch by using the volt meter at the trans plug on the purple wire and it operates like normal. Today I opened the transmission back up and checked all of the valves that have anything to do with lock up hoping to find a stuck valve and all moved freely. Right now I am out of ideas on what it could be.

 

Test the pressure switches that are screwed into the valve body.

 

I did forget to mention that I noticed that on my scan tool 4th gear always displayed engaged no matter what gear I was in so I tested the pressure switch and it was bad so I replaced it and now it appears to be working normally, shows disengaged untill it is actually in forth gear, and that is the only pressure switch in the trans.

 

I have heard of some people running this converter that had lock up problems I am now thinking of that this might be my problem. Any other ideas???

 

probably time to replace it.

I also had an ACT 9.5" converter from pro-built when I was still running an automatic about 3 years ago. The lockup in my first converter lasted 100 miles. ACT replaced it free of charge and it was fine for a year or so until I sold the trans and went with a t56.

suggest you look at the vigilante and yank converters. pricy but SO worth it.

 

Did you lose the lockup all at once? or slowly?

 

all at once, I also replaced the brake switch that controls the lock up and also didn't fix it.

 

I beleive that I ave never used my free stall change. If it is in deed the converter that is bad can I use that to get it repaired or is that only valid for 1 year. Also how much would it cost to repair????

 

I also purchased one from probuilt about 3 years ago. Lost lockup in the first 100 miles as well. Returned it ,got it back ,and lost it again. I took it out and threw it in the shed and went back to stock at that time.

 

my act lost lockup all at once as well.

the transmission itself was awesome and worked like clockwork till the day I sold it, and the new owner (from what i've read here on TGO) is continuing to enjoy it.

 

That is why I went with Edge torque converters, he would cover any problems with his torque converters pretty much without question, if he had any. I will ask Andre at Edge to see if he will fix this for you, and get back to you.

 

Sounds great!!

 

Have you ever found anything out yet??

 

I will call him tomorrow, he should be back from vacation about now.

 

Call Andre at Edge torque converters, and make the arrangements of getting the torque converter to him. There should be very little charge for the work, mostly shipping costs.