Hello all.
I've got an '85 Iroc Z. Used to be 5.0 tpi stock. Now is a 383 carb but still retains the original 700 r4. I was told it was rebuilt and has a 1800 stall with lock up. But I have no idea how to prove this easily. My issue is that running around town at low rpm it seems to want to jerky jerk like its trying to lock up but can't. Out on the highway under heavy load it pours through the gears at no problem. Is it the TCC that's causing this and how wouldni go about fixing this...easily and as cheap as possible. This will be a full restore project for me but I need and want it to run well now until it gets put away for the winter. Any help would be appreciated my fellow thirdgen fanatics. Thanks in advance.

 

Please fellow 3rd gens. Help.

 

One quick way to see if it's the the TCC is to unplug the wiring connector on the driver's side of the transmission and see if it still does the jerky motion thing . The only thing in our 700R4 that is electrical is the lockup / All gear shifting is otherwise mechanical . If the problem goes away then yes , further TCC troubleshooting would be needed .

 

Thanks for the reply. I pretty sure its the tcc. The computer is gone. Does the tcc get any signal from it for operational purposes?

 

Yes , the TCC is supposed to be told when to engage/disengage by the ECM . With the ECM gone , the normal means of control for the TCC is gone also . Now , whomever removed the ECM may have tried doing an end run around having the ECM control it by doing who knows what to the wiring and you need to determine exactly what is going on with it to further diagnose it . If the TCC has been "hotwired" , it's possible the jerking is the TCC being engaged when it shouldn't be , like at low speeds for example . There are kits to run the TCC as a stand alone entity , not controlled by an ECM but instead by the devices in the kit , and the proper install of one of those kits is the only practical way I know of to run the TCC without the ECM . You can still tell if it's the TCC by unplugging the plug I told you of earlier , with the plug unplugged the TCC has no way to get power .....

 

Excellent. I will try that and let u know what I find out. Thanks man. Really appreciate it.