HCR13

iTrader: (5)

So I've been having issues for a while with my 700R4. At first I noticed my transmission wasn't going into overdrive. So I searched here different issues and by making a temporary lockup switch at the ALDL port and it would lock when the switch was flipped so I was happy I found the solution (bad brake switch). I left the switch on the port so I can manually control it until I could replace the brake switch. Somewhere in there, I accidentally (forgot) left the torque converter locked up while in city driving. I was at a light and noticed a slight hesitation so I gave it more gas and it continued like normal. Execept now its not locking again. No matter if I have the temp switch on or off nothing happens. I fear I might have broken something. I've done a bit more research and I'm not sure what it could be. Do you think maybe I broke the tcc solenoid by not turning off the switch, or worse, do you think I broke the torque converter clutch? The transmission is stock and has about 150k original miles. Other than this issue, it works completely fine. My current haste is because I have a very long trip coming up in a couple of weeks and I would really love my 26mpg back... I'm not too worried about the overheating issues now because its getting cold outside and the transmission shouldn't get too hot...

8t2 z-chev

is it shifting into 4th gear?,converter lock shouldn't
make that big of difference if tranny is getting into 4th
(OD),I don't think leaving the TCC engaged would've
damaged anything-just put more load on the engine at
low speeds.

HCR13

iTrader: (5)

yeah, it engages into all gears, but that last "shift" doesn't occur since the TC doesn't lock up...

HCR13

iTrader: (5)

any other opinions/guesses?

z377camaro

i am having the same problem if you figure it out let me know

naf

iTrader: (7)

Was your temporary switch bypassing the brake switch or jumping pins A and F on the ALDL?

HCR13

iTrader: (5)

jumping A and F pins...

naf

iTrader: (7)

That narrows the issue significantly. Unless you're willing to open the tranny, the most you can do is verify that the signal is getting to the pigtail that plugs into the case.

I've chased down a few lockup problems in the past but each turned out to be outside the tranny, usually sensor related. May want to ping some of the trans gurus.

HCR13

iTrader: (5)

ok, I was planning on checking the pig tail anyway, I'm also going to drop the pan and check out the solenoid. Did v6 thirdgens come with 700r4's? if so, do you know if the stall converters were the same?

naf

iTrader: (7)

V6's came with 700R4's, but with a 60 degree bellhousing. Can't tell you from experience if the TC is the same, or if it has a more favorable stall (I know the 4th gen V6 had a higher stall than the V8s). A popular swap is an S-10 converter. There's a thread or two on that swap somewhere.

When I had my trans rebuilt several years ago the shop installed a TC from a similar year corvette that has a street friendly 2000-2200 rpm stall. Much improvement over original.

z377camaro

I have tried that switch through the aldl it did not work for me. It would try to come in but would not stay engaged and that was at high speeds.

ed o

your t.c.c. sol. requires a power and ground. check to make sure you're getting both or it won't lockup

HCR13

iTrader: (5)

thanks for your help guys but I figured it out. Turns out I had a bad brake switch all along. I had the original one that came with the car and I guess it went bad. I thought I fixed it by playing with the metal pins inside. But I went to the junkyard this week and just thought "what the heck" and got another brake switch off a Camaro. I just put it in, took the car for a ride and I have my t.c.c back! Now with this issue resolved, is there a way to make a switch so the tc wont lock up? I know it seems counter productive right now, but I did notice I had better "power" (higher rpm) when I hit the throttle. So it would be nice to have the option to turn off the lockup when I need to pass a car on the highway (instead of mashing it and waiting that extra second for the car to get into the power band)...

naf

iTrader: (7)

Just wire in a toggle switch to either wire that goes to the brake switch. Open the circuit and it won't lock up.

The brake switch is the last leg to ground for the lock up circuit. I should have remembered that it completes the circuit even through the ALDL.

turbinator3

when you say the brake switch was bad, explain just what switch and where? my 86 305 will not lockup in od and the rpm's are running very high (2500 at 65 mph).

naf

iTrader: (7)

There are two switches on the brake pedal lever. One for the brake lights and one to disengage the TCC lockup. If you have cruise control your TCC switch will also have a vacuum line attached that will open when the brakes are depressed and shut down the cruise. The TCC switch is the last leg in the lock up circuit before ground.

You can test your switch be disconnecting the two wire plug and checking for continuity with brake pedal at rest and open with brake depressed. Wouldn't hurt to verify continuity to ground through the plug wire-only one wire should test 'good' to ground. It's not too uncommon for these switches to die with old age.