• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

'91 700r4 to '94 4l60e swap gone bad

A

alaskanguy

New Member
Messages
5
Reaction score
0
Location
alaska
The 700r4 in my '91 went out and this is before I knew how easy they were to rebuild, so I decided to put a 4l60e in it. If I still had the old one I'd rebuild it and put it back in. I swapped computers and wiring harnesses- my truck is a 5.7 350 and the new trranny and computer came from a '94 yukon also with the 350 5.7.
And now the truck won't run hardly at all. It starts up and goes like a champ for a few minutes and then bogs down and backfires and on and on until it dies. Sometimes it'll start right back up, other times it won't start for anything and then a week later fires right up.
What do I do?
 
Did you swaqp over ALL of the electronics? The timing module and all kinds of other things changed in 93 when they went to the 4L60E and the earlier stuff will not work properly with it.
 
I did not. I'm pretty new to all things mechanical and did the swap under the direction of a guy that apparently didn't know as much as we both thought.:rolleyes5:
What all do I need to swap? The timing module makes a lot of sense as it seems to be fine and the gets progressively worse. Any idea of where to find a list of what needs changed or can you list it off the top of your head?
 
Timing module, EGR valve and solonoid, throttle body, entire underhood and trans harness, VSSB module, and parts of the underdash harness. I know sometime around 93 they changed the VSSB/DRAC module to the dual sided one. The ECM's on the 2 are a good bit different. The EGR valves changed sometime in the early 90's so I would change it to be safe. The oil pressure switch was different on the earlier models(not sure of when the changeover was for that one). And I know the timing modules would change from year to year and model to model as each ECM had a different timing/knock module for it. Later models didn't even have one in it as the ECM handled it all whereas the earlier trucks definately had one. Also make sure you have the right harness hooked up to the ECM as some of them have the same connectors but are pinned out differently depending upon which PROM chip the ECM has in it. In all actuality you would be money ahead to put it back to the 91 and swap your 4L60E back to a 700R4.

The 4L60E is a slighly better trans IMO, but not enough better to warrant all of the trouble you will have to go through to get this traightened out. Also head over to www.fullsizechevy.com as they have ALOT of good gasser info for the TBI trucks.
 
All right well thanks much! Going back to the original would be much simpler it sounds like. From the engine back everything is out of the yukon- will I need to swap more than just the tranny and transfer case or will the drive shaft hook up fine?
 
i'm in willow. Does anyone know of a cheap stand alone computer that would let me keep the 4l60e on there? or is that a super expensive option?
 
Nice!!! I guess it's a good place to be. You wouldn't happen to know of any wiring harnesses laying around that would fit my truck, would you? =-)
 
Personally I'd go back to the 700r4. Pretty simple rebuild according to my brother who also lives here in Willow
 
You must log in or register to reply here.
Back
Top