9" Lift, 37" tires, 3.23 gears. Can I tow a 7000lb trailer?

Cnadianff · March 22, 2019

Need some advice. I have a 2015 Sierra 1500 Denali with the 6.2, 9" Lift, 37" tires and 3.23 gears. All the modifications were done by GM so should be done right. I just bought a 7000lb travel trailer that's been our dream. I also bought a weight distribution hitch with sway control.

I really want this trailer, really love my truck and don't want to have to change the gears. How much am I pushing it? Does the 8 speed transmission compensate enough for the tire size? Any other concerns?

Thanks in advance!

Edited March 22, 2019 by Cnadianff

Jacoby · March 22, 2019

You’re not pushing anything. The truck will pull that trailer no problem. It’s gonna be an absolute dog while doing it but it’ll do it.

Donstar · March 22, 2019

Is the 7.000 lbs net or gross? As Jacoby suggested, it will probably pull the trailer but I bet you will horrified at the fuel costs. If you're not concerned about mpg's, your travel range between fill-ups will be frustratingly frequent. When I purchased my travel trailer last year, I was apprehensive about my power to pull a travel trailer through mountainous terrain. My truck did fine but I pay for it at the pump! If I was to do it over, I'd insist on arranging for a test tow at highway speeds and hilly terrain.

TXGREEK · March 22, 2019

Need some advice. I have a 2015 Sierra 1500 Denali with 9" Lift, 37" tires and 3.23 gears. I just bought a 7000lb travel trailer that's been our dream. I also bought a weight distribution hitch with sway control.

I really want this trailer, really love my truck and don't want to have to change the gears. How much am I pushing it? Does the 8 speed transmission compensate enough for the tire size?

Thanks in advance!

Congrats, sounds great, with that setup and now towing 7000# trailer along with additional gear and people added too, at max towing capacity, I’d look at re-gearing the front diff and rear end for much better hauling experience. Good luck and don’t forget pics!

Sent from above

aseibel · March 22, 2019

27 minutes ago, TXGREEK said:

Congrats, sounds great, with that setup and now towing 7000# trailer along with additional gear and people added too, at max towing capacity, I’d look at re-gearing the front diff and rear end for much better hauling experience. Good luck and don’t forget pics!

I'd look at buying a Z71 with 3.42 gears and OEM sized tires.

But paying $2,000 to change to 4.10 gears with 37" tires would accomplish the same thing.

reardiff · March 22, 2019

3.23 so you must have the 6.2? This in itself will be a big benefit over the 5.3 in your situation. I'm sure someone on here can do the math but the 37's will effectively make your 3.23, 3.08 or possibly even lower. Like said above it may pull it but would perform much better with a re-gear. If you plan on keeping the 37's I'd re-gear, but that's easy to say when I'm not paying for it ;) You'd likely also notice a decent performance boost when not towing as well, maybe even pick up a mpg or two around town.

Logan Lanfear · March 22, 2019

It wont be fast. Other than that, should be fine as long as your tires are load rated.

TXGREEK · March 22, 2019

I'd look at buying a Z71 with 3.42 gears and OEM sized tires.
But paying $2,000 to change to 4.10 gears with 37" tires would accomplish the same thing.

He’s asking about his current setup with a 9” lift with a 6.2 and 323 gears. Don’t think he’s interested in getting rid of his truck for a stock looking Z71. Changing gears would be about the only thing he’d have to do along with a new cann tune like a SuperChips and be done with it.

Sent from above

SierraHD17 · March 22, 2019

It's like having a 2.73 or 2.56 gear and then a tire and rim combo that is a good 60 lbs or more over stock. I don't know why people always can pay for the lift and tires but can't deal with the gear swap lol.

Edited March 22, 2019 by SierraHD17

bshort · March 22, 2019

37's with 3.23's??? 4.56 gearset would be better. Give the trailer a pull in the hills....you'll be wanting them 4.56's real quick.

kennerz · March 22, 2019

1 hour ago, SierraHD17 said:

"It's like having a 2.73 or 2.56 gear and then a tire and rim combo that is a good 60 lbs or more over stock. I don't know why people always can pay for the lift and tires but can't deal with the gear swap lol.

Voice of reason here. Towing with 37's That's a double Whammy. The 3.23 on a 6.2 is good for a stock weight /diameter wheel. Like mentioned above the total increase in mass per wheel is extreme, plus the increase in diameter then throw in a fully loaded trailer add at least 2k to the 7k dry trailer.

As was mentioned this needs the 4.56 just to be workable. I would do it just for everyday driving anyhow.

aseibel · March 22, 2019

2 hours ago, TXGREEK said:

He’s asking about his current setup with a 9” lift with a 6.2 and 323 gears. Don’t think he’s interested in getting rid of his truck for a stock looking Z71. Changing gears would be about the only thing he’d have to do along with a new cann tune like a SuperChips and be done with it.

I know. I'm just saying. He turned his high power truck into something that looks good but is ineffective at towing.

Now lets sink another $2,000 into it to make it perform the same way mine does with no mods. That's all.

If he wants to tow well with that truck, a gear change really is the only option.

Edited March 22, 2019 by aseibel

TXGREEK · March 22, 2019

I know. I'm just saying. He turned his high power truck into something that looks good but is ineffective at towing.
Now lets sink another $2,000 into it to make it perform the same way mine does with no mods. That's all.

If we wants to tow well with that truck, a gear change really is the only option.

I couldn’t stand owning a stock looking truck, nothing bad about it just personal preference. Always room for improvements that’s why I got a lift even though still capable of towing same factory oem rated weight I’d still get new gears.

Sent from above

Cnadianff · March 22, 2019

3 hours ago, reardiff said:

3.23 so you must have the 6.2? This in itself will be a big benefit over the 5.3 in your situation. I'm sure someone on here can do the math but the 37's will effectively make your 3.23, 3.08 or possibly even lower. Like said above it may pull it but would perform much better with a re-gear. If you plan on keeping the 37's I'd re-gear, but that's easy to say when I'm not paying for it ;) You'd likely also notice a decent performance boost when not towing as well, maybe even pick up a mpg or two around town.

Thanks reardiff, yes it's the 6.2

Cnadianff · March 22, 2019

1 hour ago, TXGREEK said:

I couldn’t stand owning a stock looking truck, nothing bad about it just personal preference. Always room for improvements that’s why I got a lift even though still capable of towing same factory oem rated weight I’d still get new gears.

Sent from above

I couldn't either. This is her and other than this issue I just came up against, couldn't love the truck more.