What changed on the 4L80E between 2003 and 2004?
 

I was looking at some interchange information, and it looks like the 4L80E from about 1999-2003 all interchange, and then there is another interchange listing for 2004 and up. (I found this for 2WD transmissions - didn't check 4WD)

What changed between 2003 and 2004? Are they still compatible?? Is the wiring or electronics different?

-Dave

In 04 the case and pump changed. When using an 04 or later case you need to make sure that you have the later pump or a modified early pump. The issue is where the cooler oil circuit is located in the pump gasket area. Vince B

they also made a change to the v/b, what i dont know, but its listed diff
i have been trying to find a 2004 v/b for my spare trans, i used it when i replaced the man shift v/b i built in my other trans

Will a wiring harness from an '03 truck work on an '04 4L80E transmission? Would you have to get the PCM reflashed?

94- present should be same harness. Reflash not required.

My 4L80E (from a 2003 Express van) has a gear selector switch like the top unit with two plugs, and my harness (from a 2006 2500 Sierra 4WD 6.0/4L80E) has a gear selector switch like the bottom picture with one big plug.

http://www.buyrcars.com/4L80Econnectors.jpg

Now what do I do?!

Can I just buy one of the new gear selector things (as pictured), install it, and use the 2006 harness? Or do I have to buy a the pigtails for the old style connector and splice them over over to the 2006 harness?

Is the newer style selector switch used on any other GM transmissions? (Ex GTO, Corvette, etc?)

Anybody want to sell me the part(s) I need to make this work??

What vehicle is this going into? If its a car, you won't even need that box.

It's going into a Jaguar XJ6 with a DBW Corvette LS1. I am going to use the existing Jag shifter linkage. Of course it's RWD.