I just replaced the 700 tranny in my 87 GTA. The origional tranny had the electrical connector disconnected so when I hooked it up it would vibrate and surge. This was a high mile tranny and slipping so I figured it was just the tranny.

Last night I installed another 700 and it surges with the TCC connector connected. It behaves fine when it's disconnected.

What can I check to see what is wrong with the circut. Is it likely I need to replace the ECM?

 

Does it surge after shifting into 2nd? I had problems with my Accel computer not controlling the t/c correctly and I put in a manual switch, when I forget to turn it off it surges/lugs when it shifts into 2nd. You might try bypassing the computer control and put a manual switch in to see if it works properly when done manually.

 

I only notice it in 3rd and 4th gear.

I did some reading on this and have a couple of ideas for things to check.

A prev owner had bypassed the lights for the gauges with a switch and it appears to be the same circut that powers the purple wire with 12V. I haven't checked it yet but will later today. I'll try grounding terminal F on the ALDL first since that is the easiest thing to try.

 

new torque convertor or the old one reused?

 

I didn't use my origional tq conv. I used the one that came with the newer tranny. It isn't new, just new to me.

Gotta be the circut to the tranny. The odds of 2 of them in a row doing the same thing has to be small.

 

right, just trying to verify and clarify simple stuff out first

 

Ok, purple wire at the tranny connector recieves 12v and when the brake is pressed nothing. That is right.

F ALDL connector grounded makes no difference. Surges with or without it being grounded.

The scan tool is reporting that 4th gear sw is on when in 4th gear.

That covers all 3 wires.

Since the connector has been disconnected for so long and has some corrosion on the terminals, my guess is it is not making a good connection. Can't really reach the terminals easy to clean them either.

Gonna go to the scrap yard tomorrow and pick up a terminal and see if that fixes it.

 

One other thing, the car is an 87. The tranny I pulled out was from a 88 IROC. The one I just put in is from an 89 IROC but the first s/n digit is an 8 so it was built in 88.

Are there any tranny internal wireing differences between 87 to 89?

 

Tried hooking it up with a new electrical connector and manually wired. Gave it a 12 volt source for the purple wire and ground with a switch for the negative. Engaged the circut at an OD speed and even throttle. Still surges.

Gotta be something in the tranny or tq converter. What are the likely culprets?

 

Actually, I would first look at the ignition system. Plugs, coil, wires, cap, rotor, pickup coil, ignition module. Then look into the EGR. I know it sounds crazy but it just may be the problem. Without the TCC locked slight problems in the engine don't get transfered through the TC. Once the TC is locked they do.

RBob.

 

Plugs, cap and coil are a couple of months old. I have a spare dist. I could drop in.

The engine is worn out. It's running ok but down on power due to high millage. I am about to replace it.

Hope that's what it is. No fun installing a tranny without a hoist.

 

It's working! Nothing has changed. I was about to remove the temp wires after one last drive and tried it one more time. No surge when locked up. Came home and drove it up on the ramps and hooked the stock connector back into the tranny and that worked too.

I have no explanation as to what happend. Could there be a big air bubble or something hiding some where in the tranny or TQ converter? I've only put about 50 km's on the tranny since installing it.

I've installed a handfull of trannys over the years but never seen anything like this happen.