[Bruce Wang]

I have a 95 Chevy 4x4 3500, single rear wheel.
Originally this truck was equipped with a 6.5L TD and 4L80e.

I bought the truck after someone had a light wreckin the front that punctured the oil cooler. I guess they let the engine run with no oil, because it had a knock down low.

So.... I took the 6.5 out and put in a 5.7L from a donor 96 c2500 (8-lug version)..
I installed all the wiring from the 96, but I left the 95 4L80e since it is a 4x4 and the 96 had a 2wd 4L80e.
The enigine is running perfectly, but the trans is acting weird. It shifts late and when it does shift it shifts HARD!

Everything I could find before I did the swap said the 95 and 96 trans interchange. The only thing I don't have plugged in is the wires that go to the transfer case. I didn't think they would affect anything since the 4L80e has the speed sensors in the main housing and there are no extra plugs on the 2wd harness. Aren't all the plugs in the transfer case for 4x4 operation only?

So basically I need to know if there is anything different between a 95 6.5L 4x4 4L80e and a 96 2wd 5.7L 4L80e. If so what can I do to make it work correctly.

This is the last wrinkle to work out on this swap. After I get this fixed I can start driving this thing.
Any suggestions??
Thanks

[airworld2]

4x4 use speed sensor on trans fer case for turbine out put speed sensor or toss, this need to be connected.4x2 used different set up with sensor the case you have may not contain the out sensor hole drilled out.4x4 units didn't need them

[Bruce Wang]

Hmmm.. The 4x4 tranny had the same 2 speed sensors in the main body, just like the 2wd one did.



I guess I am gonna have to find a 96 gas with 4L80e and manual transfer case to compare it to.

I think you are on the right track with the speed sensor causing the problem. Now, I just have to figure out where to splice in.

[Bruce Wang]

I unplugged the rear sensor in the main body and spliced the wires to the sensor on the tail of the transfer case.
It seems to be shifting right now and the speedo is working correctly.

I'm still puzzled by the fact that the 4x4 tranny had the 2 sensors in the tranny like the 2wd. I wonder if all 3 should be wired up somehow.

I'm trying to locate factory service manuals for a 96. Maybe those will answer the questions.