I'm driving an '82 Elky with a 350/330 Vortec crate motor, 700R4 trans and an 8.5 inch Grand National diff with a 3.42 posi. The trans is a stock overhaul from a now defunct shop, and I got the car in its current condition. When I got it, the 1-2 shift was very early and harsh. I adjusted the TV cable and now 1-2 and 2-3 are nice. It goes 3-4 when it should, but immediatley locks up and starts to lug unless you are winding it up good. It will not unlock and downshift unless you really jump on it. If it shifts 3-4 at 2500 rpm, it drops to 1500 and lugs. If you slow down then accelerate it will not unlock or downshift and goes as low as 900 rpm, at which point I shift to drive by hand to jump on it good. I've had a bunch of 700R equipped cars, and none of them ever did this whether they were factory or retrofits. What might be going on here? The car is unpleasant to drive as it is. Thanks!

No ideas?

my does the exact same thing
would love to know how to fix

I had one put into my 86, the mechanic turned it into a hydro lock up type and did away with the electronic lock up. He had to adjust the TV cable until it was fixed and found the correct presure. What you described is exactly what mine was doing.

You need to wire in a vacuum switch to cut off the converter lockup under load and in coast position.

Hook up the vacuum switch to ported vacuum and it will stop the lugging problem you have.

Jake, how would I do that? Is it in the vac line that goes from the intake to the trans? Where can I get the switch?

GM PN 14014519

There shouldnt be a vacuum hose going to a 700-R4.

You can buy a complete kit like jake is talking about, that comes with the 4th gear pressure switch, brake switch, vacuum switch, and all the wiring harnesses from painless wiring. I installed a kit on mine from B&M, that uses a speedsensor, that goes into the speedometer cable at the transmission, and has an adjustment to raise the lock-up points based on mph. I've installed the vacuum type setups, but still get some lugging on the engine, but It won't allow lock-up until it is in 4th gear.

On the others I've had, I grounded one side of the TCC solenoid, and ran the other side to a 4th gear pressure switch, then the other side of the switch went to a brake switch, then to 12 volts. They all worked perfectly. I can't see where the vac switch would be installed. Vac fron carb to switch, but where from there?

Dave.

The 'normally closed' contact of the vacuum switch has to be wired in series with the circuit you just described.

Rob

Ah! I see now, thanks!

check the trans fluid my lugged we even played with the tv cable and it was still the same, come to find out i was a quart low on fluid.

Go to the salvage yard & find a switch like this.

http://partimages2.genpt.com/partimages/494891.jpg

That vacuum switch can be found in 82 Chevy/GMC 305 vans.