Researching 4L80E to NV4500 Transmission Swap

[trbankii]

I’ve got an NV4500 in the K2500 and am pretty familiar with its idiosyncrasies. The “mechanical” part of the swap doesn’t worry me too much - just the electronics. So the 4L80E “missing” the ECM (such as in a mechanical injection swap) isn’t a problem for me. I’m just concerned about the ECM wondering where the 4L80E got to…

[Edahall]

I might be wrong but without the 4L80E in there, the check engine light might illuminate. That would be a concern if inspection in your area requires the CEL to be off.

[trbankii]

We do have annual inspections here, so a CEL would be an issue that would need a resolution.

Any idea where the connection between the transmission and the ECM would be? Would it be a plug into the ECM? Or a connection in the wiring harness someplace?

I wouldn’t expect the 4L80E to work properly if I unplugged things, but I could see if the CEL comes on or if any codes are set.

[Edahall]

There should be a connector that plugs into the transmission itself. However, the CEL may not show up until it is being driven and only under certain driving conditions. The ECM monitors torque converter slippage and it'll throw a code when it notices the converter not unlocking.

The fix is to find an ECM out of a manual transmission truck with the same engine and same year. Ebay would be where I would start looking.

[trbankii]

Thanks for the information. Just seems strange that people aren’t mentioning the computer part of the swap.

[Edahall]

I did a search and did find someone who did this swap and had to swap out the ECM to clear the CEL. Other than that, I suspect many just pull out the bulb on the CEL.

[trbankii]

Looking at Hypertech’s chips, they do LIST separate chips for automatic vs. manual transmissions.

Near as I can figure out, you need the PROM and possibly the CALPAK from a manual transmission vehicle to plug into the ECM - or the whole ECM with the proper PROM and CALPAK.

Unfortunately, it looks like you have to physically change the chips as the early ones aren’t able to be reprogrammed.