4l80e head scratcher.. need help

[Mogman]

ok, but you are wrong, sorry. It is not "in the shifter"

In 4l80es, the NSS is on the driver side of the transmission. It is a large black component with a large electrical connector or several I have owned several, and had similar issues. Limp mode can be enabled with a fault in this switch. Safety thing, go figure.

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Further @Mogman.........if you know the NSS is not the culprit, then what would solve the OPs issue?

You have owned several on HMMWVs? I have never seen that switch on a HMMWV, but I don't get to play with the latest (ECV/REV) trucks