96 Tahoe - Needs Flood Clear to start, no O/D

[rcotteleer]

I have a '96 Tahoe with 95K miles. While driving at ~65 mph the other day I noticed the it would not shift into overdrive, on a downhill stretch, it eventually did. All was fine for the balance of the trip to my appointment. After my appointment, it would not start until I pushed the pedal all the way to the floor (flood clear mode?) at which point it started and ran fine. On the trip home it would not shift into O/D under any circumstances. From that point on, the symptoms are the same, requires flood clear to start, no overdrive, and a significant amount of "ping" under light load. No SES to date.

Any Ideas before I head to the shop?

[2000CAYukon]

Originally Posted by rcotteleer

I have a '96 Tahoe with 95K miles. While driving at ~65 mph the other day I noticed the it would not shift into overdrive, on a downhill stretch, it eventually did. All was fine for the balance of the trip to my appointment. After my appointment, it would not start until I pushed the pedal all the way to the floor (flood clear mode?) at which point it started and ran fine. On the trip home it would not shift into O/D under any circumstances. From that point on, the symptoms are the same, requires flood clear to start, no overdrive, and a significant amount of "ping" under light load. No SES to date.

Any Ideas before I head to the shop?

I would say that they are most likely not related.

Flood clear is either the fuel pressure regulator or leaking injector poppet.

No going into overdrive could be a solenoid or valve body issue.

Ping can be lots of things.

A fuel pressure test is in order (and check to see if it holds pressure after the engine is shut off).

Fairly hard to diagnose the tranny over the internet. However, if I was to guess it would be this http://www.transmissionspecialty.com.../77942-01K.htm

Edit: If you truely lost 4th gear (as apposed to not having TCC lockup like I thought above), then it maybe this http://www.transmissionspecialty.com.../77964-08K.htm
//2000CAYukon

[rcotteleer]

Put a scanner on it (free at advance) and it was throwing a P0118 coolant temp sender high DTC. Did a little research, bought one and it turns out that was the solution..... $11.88 + tax.

BTW, I was mistaken, it was shifting to O/D, no lockup was the issue.

Thanks for the help