2011 tahoe first gear issue

[jhous09]

Not that im aware of but perhaps there's a way to look it up in GMs online diagnostic web interface but that's just a wild ass guess.

Best way is to look at the tehcm itself...

When programming it and it asks for the tun, is it asking for the new or old one? And the decal that it shows when it asks for it doesn't look like the one that was on the original transmission