I have a 94 chevy that I just bought not knowing some one had changed the 4l60e. They replaced it with a turbo 350 the problem is the truck does not run right without the electrical pluged into the trans is there any thing i can do to make this trans work  

this is one of those things for mud or snoman to handle. they will be along soon.  

Let me guess, this is a lifted truck that someone fried tranny in with stock gears, swapped tranny type to try to "fix" it rather than gears and then found out it did not work as planned and then sold it to you. Quite honestly, you need to get another 4L60 and put it back in truck. That tranny is controlled by ECM and talks to ECM too and it is not present. Further more this is really a pointless retro swap to begin with. The 4L60 has a deeper first gear than THM350 (3.06 vs 2.52) and OD. Typically these trannies fail because people fry them with tall effective drive ratios when they fail to regear truck properly and tranny does a slow bake riding stall in drive and OD until it fails and then they blame tranny not the configuration of vehicle. You need to bite the bullet here and fix it right. You may also have legal grounds to sue if you choose because though used is generally as is, if they swapped trannies out with something that is not made for that model truck and never told you about this type change they bordering on willful fraud and you have grounds to recover.  

I've done both 350 and 400 swaps, due to persistant ignorance, one 95 and a 97....they were diesel powered and had no side effects, I can see the check engine light being on but for it to not run right? I dunno.........maybe there is some fancy resistor plug-in thingy that'll fix that, never heard of it though.

how about snaping off a pic of the tranny pan and send it to my e-mail, even a crappy cell phone pic will do perfectly, (click my screen name) I can post the pic if you have trouble, that way there will be no question as to what tranny it is. I'd also be interested to see how they hooked up the Throttle Valve (TV) cable for the 350 transmission on the 94. I had a little head scratching on that matter.  

The silly part of this retro swap is that the 700R4/4L60 is based off a THM350 with different first and second gear ratio and OD added. The 4L80 is nothing but a THM 400 with a electronic valve body and OD add. If you drive these trannies in "3" with OD locked out and not Drive they are basically the trannies they replaced except for the gear ratio difference in 700R4/4L60 and electronic valve bodies. They fail because when driven in drive they upshift into 4th/OD when they can and because the effective gear ratio is so tall unless they regeared truck for bigger tires that the converter cycles between lock and unlock and ride converter stall trying to pull gear ratio/load. The down shift mode is 4th lock to 4th unlock then 3rd unlock if 4th unlock does not work. (when converter unlocks in 4th and you feel a big RPM jump like a gear down shift it is because gearing is so tall that engine suddenly jumps up 500 to 700 RPM or more on stall and starts its slow bake.  This causes a lot of heat over time and places a lot of stress on OD clutch that it was never designed to take. The result is tranny failure and the tranny being blamed not the nut behind the wheel. If you are to cheap to regear a truck with these OD trannies, at the very least do not us drive postion on shifter and do not try to tow in OD with a 700R4/4L60 even stock. Use "3" postion on shifter. Both 700R4/4L60 and 4L80 can go to converter lock in 3 which is the same drive ratio as drive in a THM 350 and THM 400 expect no THM 400 ever had a converter lock and only the late few years the 350 was used did it have one on some models. Lack of converter lock hurts MPG more than not using OD.  

i dont know what to tell you bigwheel, maybe call your local shop and ask them. or do what mud said, he will help if he can.  

part of the problem for the bad rap is the local shops because they have to guarantee them, which is hard to do when they are used improperly, so the mechanic who has to fix the same tranny he just got done building 18 days ago.....well you get the picture, when I build them, even a 6cyl. model, I use v-8 pistons and will fool around with steel thickness to get an extra clutch in there, this helps but still won't tow a heavy load, my guarantee is/was one year, and IF it is burnt. (operator error) YOU pay, they are so simple it's hard to screw up unless maybe you leave a shop rag in the oil pan. no matter if it's two weeks old or 355 days. like snoman explained it is basically the same tranny as a 350 even using the same reverse clutches. I no longer try making a living building tyrannies, I do still build them occasionally in what little spare time I have, the new tech crap is beyond me now, the old stuff is still as it was. growing up in this field, the old man could always tell what I was doing when he tore apart a 350 or 400 by looking at the damage, yeah.....the 15mph reverse to drive burnouts break center supports and cases. holding manual 2nd and high speed passing wipes out the band. nope, I always said just driving normally, it's not my fault.......NOT! he still brings this stuff up once in a while, and I still deny it.  

lol! yeah i think we all got some stories like that. good times!