Tcc...

After driving for about 30 mins and the car is warmed up, the Torque Converter stays locked up. How much would it cost to have the TCC solenoid replaced? Would it hurt anything just to disable it?

Disabling it likely won't work as it's in the 'plugged' position. If you were to completely disable the torque converter clutch, you can expect a rapid failure of your transmission.

They're not hard to replace.

Silicon.... hypothetically speaking, if I were to remove the computer in my car, replace the carb with a pre-EMC one, and put on an HEI destributor with vacuume advance, how would I wire the TCC solenoid on my 700-R4 transmission so that it works properly too without an ECM to rely on?

I've given up trying to get my 1988 caprice running right. I too would like to get rid of the ECM, go back to pre-computer carb with no TPS or M/S, and go back to HEI with vacuum advance.

Only thing holding me back is I don't know how to run the TCC without the computer. You could wire it to a toggle switch through the brake peddle, but you can't reasonably switch that cause if you forget, you will stall once you take your foot off the brake, and on the flip side, if you forget to engage that on the highway, the tx won't last long.

Apparently you can modify and convert the transmission to a non lockup transmission quite easily... assuming you know what you're doing. There's like a ball pin you have to remove or something. Don't know anything about transmissions, so talk to an expert. Also, getting rid of lock-up will cut into your fuel economy a bit, I"m guessing about 10%.

One other consideration to think about, after 1985 the 305 V8's apparently had a higher compression ratio, and potentially more prone to pinging. The ECM inputs feedback from a knock sensor that corrects engine timing to alleviate ping. I don't think this will work without an ECM, so you might have pinging problems. Don't know how an older vacuum advance would work in that circumstance, although I know the 1986 caprice had vacuum advance and it also had the higher compression ratio, so you might want to make sure you get the advance of a post 1985 Chevy, just to be sure its the same.


For the time being, my 1988 Caprice has a non-feedback carb of a 1983 caprice. Car runs fine with the mixture solenoid disconnected and without a Throttle Position Sensor (TPS). If you close the TPS circuit, the car will run poorly (pinging, no power, etc), cause the computer is expecting a proper feedback reading. But if you just leave the TPS disconnected, the car will run just fine without it. Your check engine light will be on though. Only problem is that your lockup converter doesn't disengage as quickly when you step on the gas, since no TPS reading is indicating a change of throttle position. So sometimes if you want to downshift quickly, you either stomp on it or manually put it in 3rd gear.

Let me know what you learn on your car. Not a fan of the feedback carb!!! The more vacuum components, solenoids, vacuum breaks, diverter valves, etc etc they put on those cars, the worse they got!

They make kits that you can add to your transmission to do that using a hydraulically-controlled electric switch. Basically, when the car is in direct or overdrive, pressure in a certain line will cause it to trip and allow electric flow through it to ground.

You can google for the kit - same kit works on 200-4R and 700-R4.

If you don't want your tcc to lockup, just unhook the harness from the transmission. I don't think it will affect the computer. I have my tcc wired to a switch under the dash to turn it on manually. There are diagrams on this page:

http://purplesagetradingpost.com/sumner/techinfo/700R4p1.html

I used the second diagram from the bottom. It seemed to be the simplest. I did not use an LED or a vacuum switch. Basically, pin A or B need 12 volts and pin D needs ground for lockup. I used this diagram, but the switch locks it up no matter what gear you are in (except 1st gear).

MY TCC has been disconnected for the past 40k miles. The transmission shifts fine, I still have the OD. It does use a bit of tranny fluid, I add maybe a quart a year total. The fluid is still red and smells ok.

I don't think that an honest shop should charge you more than $150 to change it.

Bob

My fluid smells slightly burnt. However, the tranny DOES have 134,000 miles on it... it's probably starting to slip, although it drives fine most of the time, so I'm not too worried.

capriceforever: you mentioned how unhooking your TPS sensor caused the torque converter to remain locked-up. My car runs like crap sometimes... infact, it coinsides with when the torque converter is locked up. It misses some, and has NO power what-so-ever. It also bucks during acceleration as though the timing was way off. I wonder if a bad sensor could be the cause of this? Another thing that would lead me to believe this is that sometimes the check engine light comes on and as soon as that light comes on, it runs like crap. I checked the code and it was the code for the EGR. After unhooking the EGR, the car idled a little better, but the light came on again after I disabled the EGR and the car ran like crap AGAIN, so there's a problem somewhere, and it's not the EGR. Another interesting note is that the Check engine light hasn't come on in the last 1000 miles, even with the EGR disabled. Shouldn't that light come on if there's no EGR?

BTW, my engine never stops pinging when going up hills... doesn't matter if I run 92 octane or 87, it acts the same.

One last note: the car also idles too low, but my mechanic said it's probably just a dirty throttle body.