Need Transmission advice, no overdrive/4th on a 2005z71 tahoe

[ratfink74]

Got her used a couple of weeks ago. Expanding family and needed more room. It has 77K miles on it. Worked great when we first brought it home. For the last four days it seems to have lost 4th/overdrive. Just got back from a trip to Wallyworld, never hit 4th on the way out. shopped for 20 minutes. Left to come home and the first chance it had to hit 4th it did. Had to stop at a light and never hit 4th again all the way home. tranny doesn't seem to be slipping, and cruise still works. It used to tach around 1400rpm at 55mph, now it is 2300rpm.

any suggestions? Thanks

Richard

 

[hoe]

Could be a TCC solenoid (electrical issue)
OR it could be something physically damaged.
Check fluid levels too.

 

[ktmhans]

Search for the posts from "Jay" not sure if he ever directly expressed that but youll surely find out how it works