So I'm having a really weird problem. I just got a $400 truck with a stock 350 sbc and a turbo 350 trans. When pulling up to a stop in drive the torque converter does not want to disengage. It tries to kill the engine so I have to keep my foot on the gas. I tried changing the idle, but it idles really really high in park when it gets to where it will run when in drive.

It might be an important thing to know that this truck sat in a field for a couple years. There may be a bunch of crap in the trans. I'm thinking the next thing I'll do is flush the tranny really well and change the filter. Does anyone have any suggestions?

Check the kickdown/detent cable adjustment. It regulates the transmission pressures. Miss-adjusted, or not hooked up, it will load the pressure to engage the torque converter.

Is this a TH350C with a lockup converter? If so, temporarily disconnect the plug from the side of the trans and see if the problem continues. If it goes away, you've got a short in the control circuit someplace.

The TCC lockup solenoid can also hydraulically keep the converter locked up.

This is a normally open solenoid and if it is stopped up will not allow the solenoid to exhaust signal fluid.

Thus keeping the TCC lockup valve applied and keeping the converter clutch applied.

Replacing the solenoid is not difficult[requires a pan drop].

I would try Joe's suggestion first, but if it the problem remains suspect the solenoid.

Well I thought it was a turbo 350, but I just looked and it's a turbo 400. If it has a lockup tc is that what the plug is next to the shifter on the side of the transmission? If so there isn't anything plugged into it. Does this give any clues to what my problem is? And if that is for the lockup tc what would be a suggestion for getting a control module? I was planning on dropping the pan any way to put in some new fluid and a new filter so that wouldn't be too big of a deal.

How many connectors? This could be the neutral safety switch. I don't recall ever seeing a lock-up converter on a TH400 transmission.

That terminal on the side of the trans is the kick down switch connector. The th400 has an electric kick down.

looks like a two pin. It may be the neutral safety switch because it turns over in any gear. I searched on google for a turbo 400 lockup and didn't come up with very much, so I wouldn't be suprised if they never did come with one.

That is something that can be bypassed easily under the dash. If it cranks in all gears, that is what it is. Now back to the kick-down cable, or linkage adjustment, as a possible problem. Either that, or there is an internal problem inside the transmission, or a problem with the torque converter.

If it is a two blade connector that looks like a T than it is a variable pitch converter switch used on the 65-67 th400 OR a 1970 -74 TCS (trans. controlled spark). Sorry I'm not very good at either of those but that is what they are

Well let me take that back, I thought it was a turbo 400 because it's not a square pan, but now that I look at it I'm not sure what in the heck it is. It doesn't have a modulator anywhere hanging off the tranny, and there is a cable hooked to the carb that goes to the passenger side front of the housing. Here are a few pictures

You can clearly see the starting of the word Metric on the bottom of the pan. This will not be a TH400. A clear shot of the whole bottom of the pan(including # of bolts) would be a big help in identifying it.

http://www.nastyz28.com/chevy-trans...ntification.php

It's a THM200-R4 transmission. I don't know anything about them, but that's what the profile of the pan looks like.

Okay, that is not a th400. And it does have a tc lock up solinoid in the trans. I would pull the pan change the filter and fluid. while you are in there pull the solinoid for the lock up. It is the square looking thing with wires. Some times there is a little ball that will fallout. catch it and put it back when you are done. The sol. can be checked with an ohm meter. It should be no more than about 1000 ohm if memory serves me. It it has more replace it. I think you will just find the passage plugged. These transmissions will operate with out any kind of module hooked up they just wont lock up.

Does anyone know anything about these things? From what I'm reading they are a car transmission with an overdrive. It's in a GMC 3/4 ton that I'd like to tow with. Are these things desireable? If not I'll just fix it and drive it until I burn it up and then get a turbo 350. I guess this is what I get for buying such a cheap truck, but on the brighter side the motor does run really well and doesn't smoke at all.