ok so my roommate has a 98 trans am, and his trans was doing weird things and the fluid went from fine to burnt and he started getting a p1870 code. it would lock up but the tcc slipped when power was applied.. so he got a deal on what appears to be a finishline trans with a vig torque converter out of a wrecked car his friend had.. we chalked the problem of his old tranny up to the tci stall he had in it.. well now after he swapped in that trans and converter in there is still a p1870 code with no lockup.. he swapped the lockup soleniod and the computer is commanding lockup but its not locking.

 

Well its unlikey to be electrical since you are setting the code and theres no code for the tcc solemoid or PWM solenoid electrical.
Was there and ORING on the input shaft on the new trans?

 

yeah.. its seemed fine cause he made sure to look at it before he put it in.

 

Most of the time an 1870 is set is because the TCC regulator valve bore, in the valve body, is worn. But...Other internal transmission slippage will also set an 1870.
The odd part is, you have computer command. Are you sure this isn't a wiring problem? You may want to install a temporary toggle switch on the ground side of the TCC wire, at the transmission, to see if you get lock-up then. This will help narrow down the possibilities. If you shoot me an e-mail address, I'll send you a diagram showing which wire is the TCC ground wire.
Also, remember that if a 4L60E doesn't have lock-up, you'll waste the 3-4 clutches in a short period of time.

Frank
CPT

 

I tried grounding it and didn't lockup. I tied into the wire and used a test light. The light worked at the times the converter should lock and unlock. It did lockup twice this morning. But that was a 35 mile commute.

 

If you're sending your own ground, directly at the case connector, you've only got a few possibilities Faulty internal wiring, faulty lock-up solenoid, sticking lock-up valve, or converter. since you've already changed the solenoid, we can eliminate that. Lock-up valves don't usually stick. i have seen the internal wiring come apart at the hot splice, but if it locks at all, I'd rule this out. When you ground it, are you grounding both the "T" and "U" terminals?

If this car came into my shop like this, the first thing I'd do is check what you already have. Then I'd pull the valve body, and ream it and install a Sonnax TCC regulator valve kit. while the pan is off, I'd pull the lock-up solenoid out and stick a pick through the hole in the lock-up valve retaining disc, to make certain the valve is moving, and returning with spring pressure. while the pan is off, I'd also visible check the wiring harness...as well as ohm the wires.
If none of those fix it, then I'd start looking at the converter itself. As already stated, I'd also make certain that the o-ring is on the input shaft and that it's in good condition.

Frank
CPT