[Stanley H]

Something Interesting
We have managed to swap out a 4l60e to a 4l80e on a 96 tahoe usung existing computer and it seems to be working very well. There were a few mods to the wiring a resistor and a relay added.Tranny shifts threw all gears up and down.

[speedydeedy]

How did you know where it needed a resistor and a relay?

[Stanley H]

The B solenoid uses the relay when it is On for the 4L60E it has to be OFF for the 4L80E. The resistor is used for the 3-2 solenoid so the ECM can see it otherwise it goes to limp mode and you only have 3rd.

[jakeshoe]

What about the gear ratios?
The PCM should see the gear ratio difference between the outout shaft and engine rpm and that they aren't correct.
Maybe not as accurate as the later model stuff since the biggest difference is low and the converter isn't locked then but with it in OD and converter locked, the .05 difference in ratio may eventually set a code.

In most applications you can re-tune for the 4L80E and all you have to do is repin two wires and leave one out at the trans connector.

[Stanley H]

Retuning trans is the best way to go. But we have a bunch of tight fisted people in our country who do not want to spend the money on these changes so we have to try to accommodate them as best we can. Most of our trannys are 350 th or 400 th we might have app 5000 4l60e's and 400 4l80e's on the road as we are no longer allowed to have left hand drives on our roads except existing ones.

jakeshoe
Your right on the money over 130 Kph the trans goes into limp mode anything under that speed all is ok.
Thanks for all the valuable input.