2005 Yukon Denali No Drive Gear?

[STL_Denali]

On the hwy today I went to pass someone, floored it, and the rpms’ redlined but it didn’t shift… just went wah wah wah wah wah… like there was no more gears to go into. It shifts from 1st to 2nd to 3rd… but I think im missing 4th or the drive (overdive) gear.

Ive did some searching and seen everything from fluid, to electrical to a bad tranny.

Just wondering where I should start, or if anyone has had this same expeirence and could give some insight.

I have about 165K miles on here an no major modifications to the engine (had new cat back earlier this year), and have done the 100K maintenece.

thanks in advance

 

[Nickn]

Is your check engine light on? Perhaps a transmission dtc code has been set? Issue Could be electrical or mechanical. I'm no expert but have do a valve body in my 2003 tahoe so been doing some research...

Electrical:
Shift solenoid(s) malfunctioning
PCM (less likely)

Mechanical:
Bad 2-4 servo
Bad 3-4 accumulator
Transmission Oil pump (less likely since you didn't note issues other than no od)
Valve body worn

 

[STL_Denali]

Well shit the bed... tested the TPS and flushed the tranny to no avail. No codes and didn’t see any PCM problems. Took it to a good AAMCO shop here. They looked at it and determined it needs a rebuild.

$2100-$2500 bones.... I really hope this sets me up for at least 2 more years without nothing else major.