hello guys im new here but have found tons of good info.i hoping you can help me out.im putting a 1999 cadillac deville northstar engine and complete wiring with the dash and all electronics in my 1956 chevy wagon.

the trans is where i need help.im using an 2008 4l60e v8 2wd truck transmission.it has the black 15 wiring plug.the original cadillac trans is a 4t80e.the 4t80e uses a turbine input speed sensor.thats why im using a 2008 4l60e because they started using the turbine input speed sensor in the 4l60e in 2008 and later.the 4t80e always had a turbine speed sensor.i need to know the wiring pinout for the late model 4l60e black plug and the cadillac 4t80e plug.i need to know if the wiring pinouts are the same. from what i have seen the pre 2008 4l60e and 4t80e use all the same pinout except the 4t80e has two extra wires for the turbine input speed sensor.so im hoping the new black 15 wire plug pinout is the same except the two extra tss wires.then just wire up the tss if they are different.im hoping the stock cadillac computer will run this trans since all the sensors and shift solenoids
are the same.but will i have problems with the cadillac shift tables shifting the 4l60e trans because of different gear ratios.there is someone who has hacked the northstar computer (westersgarage) so i could get them changed.but i would rather not have to if the cadillac computer will just shift it like a caddy since this is just a cruiser.

i have changed the 4l60e shifter module(the electrical part that connects to the shift linkage)from the new one plug style to the older two plug style than matches the cadillac wiring so thats done.also i have had to change the v8 bellhousing on the 4l60e to a 2002 v6 camaro bellhousing so it would bolt to the northstar engine and im getting a custom torque converter made.

any help is greatly appreciated

 

If the 4T80e is like the 4L80e, its ISS is 40 tooth, and is after the overdrive planetary (so overdrive doesn't change the ISS RPMs in relation to the VSS RPMs). Also, the 4L70E with an ISS is 17 teeth, and is on the input shaft, so overdrive does change the ISS RPMs in relation to the VSS RPMs.

You might be better off seeing if you can get a segment swap to a 4L60E transmission segment (if possible).

 

Hit up some sand rail places they use a lot of Northstars in buggies and sand rails.

 

http://www.black-ridge.com/download/TCM4100SCH.pdf

http://www.black-ridge.com/download/TCM4102SCH.pdf

ok i found this it looks like the 4t80e uses 12 wires but the 4l70 use 13.i found out they call the trans a 4l70e after they added the input speed sensor. if you look at the connector keys the only wire the cadillac 4t80e doesnt have is the 3-2 shift wire.so will the trans run fine with out that wire.

 

I have never even seen a Northstar in a car not mounted transversely. You should ask for help from someone who has done it. I doubt anyone on here has done it with this being ls1tech. I am an unemployed GM/Cadillac drivability tech and I would not attempt a swap like this unless it was commonly done. You might be doing something that has yet to be attempted so you should just use your most intelligent interpretation of the schematic and try it. If it bolts up and you are just worried about the electronics you should just convert the 4l60e to a vacuum modulator. Then the pcm would not control the shifts and it would be a lot easier swap.

 

people have done this swap to rear wheel drive but they ditch the computer and wiring and use an aftermarket computer.i know this is an ls1 site but i have found that a lot of good info about transmissions on here.i have the dash and all the wiring in the car my main concern is if i can trick the stock cadillac computer to control the new transmission.can anyone tell me what the 3-2 shift wire does and how it works?im assuming its for the downshift but if the stock caddy computer doesnt have that wire im hoping it will run with out it.the cadillac doesnt use that wire so it must downshift using other means.if worst comes to worst and i do convert to a vacuum modulator or aftermarket trans controller will the engine still run fine without seeing the trans sensors.