1995 silverado, shifts fine no tc lockup though

[95silveraydo]

Hey guys, new to the forum. I just got another gmt400 a month ago, bought it from a good friend of mine. Anyways, the truck is a 95 but the 4l60e is out of a 94 light duty 3/4 ton chevy. The truck shifts just like it should, has 20,000 on the rebuild. I pulled a code 83 which would be a tc lockup solenoid but Ive heard that the computer in the 95s had some differences from previous years. Could any of you guys throw any ideas out there if this could be the computer not recognizing the transmission sensors or just a faulty solenoid? Thanks

 

[95silveraydo]

Ok so when i checked codes yesterday I must have reset the computer somehow, cause the overdrive worked for a short trip today. After I shut the truck off and then started on my way home again the torque convertor does not lock up anymore. I'm stumped guys

 

[VCaddy]

95 has the PWM (pulse width modulation) control for the TC lockup. 95 was an oddball year for 4L60E control, I'm pretty sure you can only use a 95 model year transmission.

That 94 transmission doesn't have the PWM solenoid, so it doesn't even know the TC lockup command from the PCM is being sent.

 

[inthechateau]

On my 98 I found the brake switch was causing issue. Fine cold but as it warmed up there was just enough problem with switch contacts it would keep TCC from occurring.