2005 yukon transmission problem

My transmission seems to stay in lower gear than needed on highway. Tach speeds are 2500 @ 55 and closer to 3000 @60-65. Is this normal?

Not normal, sounds like no shift to o/d. Any check engine lite, it is in the o/d shift position, no tow/ haul mode selection?

Mrs. Cusser's 2005 Yukon Denali AWD lost its highest gear and died Friday while she was towing the horse and trailer about 80 miles from home. Not that unexpected, with 170K on it...goes to get transmission rebuilt tomorrow....

Mrs. Cusser's 2005 Yukon Denali AWD lost its highest gear and died Friday while she was towing the horse and trailer about 80 miles from home. Not that unexpected, with 170K on it...goes to get transmission rebuilt tomorrow....

Picked up the Yukon yesterday, was diagnosed by shop as needing new transmission. They rebuilt mine, new torque converter, R&R total $2.0K. 24 month/24,000 mile warranty.

Runs nice and smooth; time will tell...

Mrs. Cusser's 2005 Yukon Denali AWD lost its highest gear and died Friday while she was towing the horse and trailer about 80 miles from home. Not that unexpected, with 170K on it...goes to get transmission rebuilt tomorrow....

I am not sure how heavy the horse and trailer are, but towing in O/D is usually not a good idea. It's extremely hard on O/D when hauling a load and it is shifting in and out of O/D. That's why the "tow/haul" mode doesn't shift into O/D.

If you are towing on a nice long stretch of flat going into O/D isn't bad, because it will stay there, but once any kind of hills, or curves are hit where you need to slow down its a good idea to kick it out of O/D.

There's actually a lever to engage/disengage while towing, has a picture like a wagon. Mrs. Cusser follows directions in the owner's manual.