Transmission problems -- ECM the cause??
 

I have a 1992 Chevy Silverado 1500 truck with an automatic transmission. The motor recently went out and I am trying to replace it with a 350 with a 4 barrel quadrajet carborater and a 1979 distributer that is hotwired to work. The only thing that's wrong is that the tranmission is acting weird and the cause I believe is in the ECM.

The old motor had the fuel injected throttle body. I've got a bunch of wires that used to plug into it but are no longer necessary because of the carborator.

Is there a way to bybass the ECM or to make this combination of components work?
Is there a new ECM I can buy that can let me use all of these components?

The transmission's symptoms: runs good going forward, no neutral, reverse tries to go forward, and drive gets 1,2,3 gear but not overdrive

Any information is greatly appreciated

RE: Transmission problems -- ECM the cause??
 

sounds like the problem is inside the trans, i wanna say the parts called the sun shell, when it (commonly) breaks u lose OD and rev.... not sure what to make of the no neutral though.

if you dont want to try crackin into it yourself, i'd say call a tranny shop and tell em what its doing, if its the sunshell i think they could fix ya up for a pretty reasonable price.

RE: Transmission problems -- ECM the cause??
 

this is the same tranny thats been in the truck??..the ecm can't kill reverse...something is not hooked up properly

RE: Transmission problems -- ECM the cause??
 

700R4? Sounds mechanical. ECM wouldn't have that kind of effect on the tranny. The linkage (kick down) might be too tight or the shift linkage might be hooked up wrong or kinked somewhere.

RE: Transmission problems -- ECM the cause??
 

700r4 transmission and it is the original....reverse is not out exactly.....when you set it to reverse it tries to go forward!!!


what is the sun shell???? Is there another name for that??

RE: Transmission problems -- ECM the cause??
 

That sounds like it could be the shift linkage not aligned properly to me.

RE: Transmission problems -- ECM the cause??
 

So does not having the fuel side of the ecm plugged in have any negative affect on the transmission?

RE: Transmission problems -- ECM the cause??
 

Only if its a 4l60e...and thats not going to kill reverse....it will just default to 2nd gear on the hiway..
if its a 700..the only thing the ecm controls is the lock up

RE: Transmission problems -- ECM the cause??
 

any way to bypass the torque converter lockup?

RE: Transmission problems -- ECM the cause??
 

unplug it...but thats not your problem..
its a 700r4?

RE: Transmission problems -- ECM the cause??
 

sun shells full name would be sun gear reaction shell

RE: Transmission problems -- ECM the cause??
 

I"m sorry for the time lapse in responding....the fuel pump went out now and I've ordered a new one.....My transmission is a 700r4....
Nobody thinks that the probably could be in the ECM?????

RE: Transmission problems -- ECM the cause??
 

The ECM is unplugged because the motor is carborated and not fuel injected anymore. How can I bypass the computer and have the transmission's torque convertor unlock when necessary?
The transmission is a 700r4......maybe I should post a new thread...how to make the silverado run without a computer.

RE: Transmission problems -- ECM the cause??
 

the trans is not controlled by the ecm..just the lock up is...she shifts off vacuum and pressure ..and good ol mechanical valves n linkages

RE: Transmission problems -- ECM the cause??
 

i did a lil lookin on alldata to be sure, and i found there are some electronic controls for the 4-3 shift that i was unfamiliar with on these trucks. if your only symptom was no OD i wouldnt rule out the ECM, but having no reverse, the ECM has nothing to do with that. the only way i can see this being ECM related problem is if gnomes placed an ECM inside of your transmission.

RE: Transmission problems -- ECM the cause??
 

does it lock up?

RE: Transmission problems -- ECM the cause??
 

Our work truck, a 89' silverado, had similar symptoms and when we took it into the shop. It didn't hit third, didn't want to downshift and no reverse. It was a few years ago but all I can remember is that the cheapest alternative was a reman tranny.

RE: Transmission problems -- ECM the cause??
 

yeah....I'd like to bypass the computer controllled lockup if it is possible......not necessarily the easiest thing to do.....Is there a way to rig a switch which unlocks the torque convertor and bypasses the computer??? I have a standard transmission I could put in but making a standard fit where a automatic should be isn't easy either....