08 Sierra Denali Gear Ratio

Litton · July 27, 2008

I'm looking at picking up a new SD and it will be used to tow a TT. However, the 3.43 GR seems a bit limiting so I have a couple of questions.

Can the GR's be changed to a lower ratio...say 3.93 or 4.1?

Does the SD share the same rear axle as the Sierra 1500 with max tow package?

Is anyone towing to the 8400 lb limit or there-a-bouts.

My other choice would be a Toyota Tundra but I'd much rather stick with the SD as I really like it for use when not towing.

Thanks for any advice.

Dick

Bish · July 27, 2008

I'm looking at picking up a new SD and it will be used to tow a TT. However, the 3.43 GR seems a bit limiting so I have a couple of questions.

Can the GR's be changed to a lower ratio...say 3.93 or 4.1?

Does the SD share the same rear axle as the Sierra 1500 with max tow package?

Is anyone towing to the 8400 lb limit or there-a-bouts.

My other choice would be a Toyota Tundra but I'd much rather stick with the SD as I really like it for use when not towing.

Thanks for any advice.

Dick

I have a YD and I have towed 6000lbs with it. The gear ratio is not too bad because of the 6-speed. First gear is super low with no trouble getting started. 6th is too tall to tow at highway IMO but both 5 and 6 are overdrive. Gears can certainly be changed but obviously you are looking at front and rear. I'm pretty sure the rear axle is the same unit in all the 1500 series.

IMO if you are really planning on towing that much weight regularly, I would upgrade to an HD chassis.

huero626 · July 27, 2008

If u really need to a truck to tow I suggest u go with a V-Max Sierra or Silverado they come with 3.73 or 4.10 gear ratio and they can tow up to 10,000 pounds. I wish the Denali would at least come with 3.73 gears that would be pretty awesome. I wouldn't trust a Tundra, if u do get one don't put a lot of weight on the tailgate cause it might break the tailgate, and all other sort of problems it has.

Litton · July 28, 2008

If u really need to a truck to tow I suggest u go with a V-Max Sierra or Silverado they come with 3.73 or 4.10 gear ratio and they can tow up to 10,000 pounds. I wish the Denali would at least come with 3.73 gears that would be pretty awesome. I wouldn't trust a Tundra, if u do get one don't put a lot of weight on the tailgate cause it might break the tailgate, and all other sort of problems it has.

I am goiing to look at the V-Max Sierra but I would really like to have the 6.2 and 6sp. That's why changing the GR might be acceptable if that's all I need to do. The SD tow rating of 8400 is OK, it just might be nice to have the lower GR for pulling 8,000 lbs up a 6% grade. However, I really don't know what the SD can do with that much TT so it's just a guess.

If the G.R. can be changed without too much fuss and bother, then I'll buy the truck and change them later if the need actually arises. Hopefully the differentials and axles are the same as the rest of the sierra line and everything just fits.

kutu · July 28, 2008

I may be wrong but I think the Denali has an 8 1/2 rear. The Vmax would be a much better choice for towing. I heard the 2009 Vmax crewcab will be available with the 6.2, 6 spd and a 3.73 or 4.10 rear.

Nick The Great · July 28, 2008

How much towing are you gonna do? If it's a handful of times a year, it will be ok. If you're doing it every weekend, you would LOVE 4.10's.

huero626 · July 28, 2008

I may be wrong but I think the Denali has an 8 1/2 rear. The Vmax would be a much better choice for towing. I heard the 2009 Vmax crewcab will be available with the 6.2, 6 spd and a 3.73 or 4.10 rear.

I heard the 2009 Sierra & Silverados are going to get the 6.2L & 6 speed auto but they are also going to come with the 3.42 gears.

Bish · July 28, 2008

You should look more at the overall gear ration as the 6L60E has really low first

6L80

1st Gear Ratio 4.027

2nd Gear Ratio 2.364

3rd Gear Ratio 1.532

4th Gear Ratio 1.152

5th Gear Ratio 0.852

6th Gear Ratio 0.667

Reverse 3.064

4L60E

1st 3.06,

2nd 1.75,

3rd 1.00,

4th 0.70

Compare the overall gear ratios when looking at 4.10's on a 4L60E

I also agree that for casual towing you would be fine but every week probably better to go HD.

bhales · July 28, 2008

You should look more at the overall gear ration as the 6L60E has really low first

6L80

1st Gear Ratio 4.027

2nd Gear Ratio 2.364

3rd Gear Ratio 1.532

4th Gear Ratio 1.152

5th Gear Ratio 0.852

6th Gear Ratio 0.667

Reverse 3.064

4L60E

1st 3.06,

2nd 1.75,

3rd 1.00,

4th 0.70

Compare the overall gear ratios when looking at 4.10's on a 4L60E

I also agree that for casual towing you would be fine but every week probably better to go HD.

bhales · July 28, 2008

i'm not sure how far or often you tow, but i have an 08 AWD sierra denali, and pull a 28 center console that weighs 11 to 14 thousand depending on how much water and fuel are on the boat. I haven't had any problems so far, but i only pull about 30 miles each way to the water.