New to me tv

I never got around to checking the ratio taking it out again tomorrow.

Tows fine in drive. Sucks gas. Air ride works well.

Much nicer than the expy

To find the gear ratio, look at the Service Codes sticker....likely in the glove box....

GU5 - 3.23
GU6 - 3.42
GT4 - 3.73
GT5 - 4.10

The sticker looks like this:


This one is a 3.42 w/locker (G80)

I had a 2004 3/4 ton Suburban with the 6L and 3.73 axle ratio and had to run 3rd gear towing the trailer in my signature as it would loose speed even on the flats with OD.

As far as I know, all of the GMT800 Denali's had the 6L and 3.73 axle ratio. Look for GT4 on your option codes listed inside the glove box door for the 3.73 axle.

Honestly, from what I know and have read, towing that kind of weight with the 4L60E or 4L65E transmissions I would be doing all of my towing in 3rd.

In regards to gas mileage, my 04 got 15mpg at best on the highway and got 8-9mpg towing. In regards to the fuel pump, I believe it has something to do with the filler neck leading to the gas tank as with our 05 that we had for 5 years I could never run the gas nozzle wide open or it would shut off.

The 6.0 liter is quite a bit more motor than the 5.3. You might be able to run 4th in tow/haul mode. Give it a try and see how it goes. I run mine in 4th with and without tow/haul, but I have 4.10 gears which probably helps.

Ill run the vin to tonight to check the gears. I asked about the gears because I had a k1500 with a 5.3 I had to run in 3rd.

Appreciate the responses ill give the nozzle deal a try next pit stop.

Hitched it to pull it out to the street after installing the brake controller.. Sagged bad until I started it and the air compressor kicked in. It leveled it out perfectly. Hopefully the factory air is reliable.

Congratulations on the new to you TV.
Related to the "I do not know what gearing it has and if I should run in 3rd gear or if I can leave it in drive with tow haul mode on."
My experience is with my Ford F150. I let the computer pick the gear. I put it in tow haul and enjoy the ride. Enjoy.

If it has 3.31 axle ratio, run 3rd, 2nd on hills.

Congrats on the new to you TV. My wife used to have an '06 Yukon XL Denali and it should pull your TT well (my 8K TT was a bit much for it). It should have the 6.2L, AWD, and 3.31 rear end. We towed once from Savannah, GA to San Antonio, TX and back one Christmas and besides using the Tow/Haul function we just put it in drive and went down the road at 60 MPH.

As far as gas...it drinks a lot and like previously mentioned...just pull the nozzle out about 1-2 inches :)

What's the hitch rating...????....Dennis

Congrats on the new-to-you TV! Let us know how it goes...