Yukon XL towing capacity: 3.73 vs 4.10

[Bart Hinder]

Just do it. You're not going to break anything. The 2500s are total tanks and completely overbuilt.

I would say just make sure you leave it in third gear, which is a 1:1 ratio, to minimize stress on the transmission. That's most likely the reason for the lower towing rating. Just lock out 4th, overdrive.

ETA: Instead of re-gearing in the future, if it was me, I'd look into upgrading the transmission to the Allison. You'd need to lift the body an inch or an inch and a half to clear the bell housing, but that would be a substantial upgrade. Should be pretty easy to find a junkyard transmission, there were hundreds of thousands of 2000-2006 HD pickup trucks built with the 8.1 and the Allison. But the SUVs didn't get the Allison, they got the 4L80/85.

Advantages of the Allison are an extra gear (it's a five speed), better ratios in lower gears to get you going with heavier loads, and grade braking.

Thanks for the great advice and confidence booster.

 

[Bart Hinder]

For a given grade (hill) or given acceleration rate, a 4.10 ratio means less torque on the engine/transmission.

IE, if everything else is the same (same hill, same speed up the hill, same load on the vehicle/trailer) it takes the exact same torque AT THE WHEEL. But the 4.10 ratio multiplies the driveshaft torque 10% more than with the 3.73. So for an equal torque at the wheel, your transmission, engine, and driveshaft is seeing only 90% of the torque.

That is the physical difference. Everything else is the same: A 12k lb trailer on the back doesn't change frame stresses etc, it's all in the drive-line torque.

Considering rated tow capacities are very conservative, you should be ok towing a load over rated capacity as long as you're thoughtful about it.

When GM rates vehicles for tow capacity they have to keep in mind that people are going to try to hook that capacity trailer up tow it down the interstate in the mountains. If you're not doing interstate, nor mountains, you should be able to exceed rated capacity by a large margin. Even if you are doing it in the mountains, just use a lower gear and keep an eye on transmission temp.

Thanks, CB. I'm a tech writer, and that is the best explanation of axle ratios that I've seen.

All you guys are great and I'm happy I found this forum.

 

[Bart Hinder]

Related tire pressure question: Door sticker says 50psi Front, 80psi Rear.
Right now all four tires have 80psi. (which is what the sidewall says and what Quick Lube did).

Any advice or concerns?

 

[Bart Hinder]

Related tire pressure question: Door sticker says 50psi Front, 80psi Rear.
Right now all four tires have 80psi. (which is what the sidewall says and what Quick Lube did).

Any advice or concerns?

I know you should always go with the placard values, but I was reluctant to dump 30psi from the front tires. I happened to be near Discount Tire, so I whipped in and had them do the free air check. They sent me on my way with 50 psi in the front, 80 psi in the rear per the sticker.

What a difference. Braking, steering and road noise improved dramatically.

 

[swathdiver]

Related tire pressure question: Door sticker says 50psi Front, 80psi Rear.
Right now all four tires have 80psi. (which is what the sidewall says and what Quick Lube did).

Any advice or concerns?

I know you should always go with the placard values, but I was reluctant to dump 30psi from the front tires. I happened to be near Discount Tire, so I whipped in and had them do the free air check. They sent me on my way with 50 psi in the front, 80 psi in the rear per the sticker.

What a difference. Braking, steering and road noise improved dramatically.

Truth to be told you could run the rears at 50-60 psi when you're not towing too. The truck stil has LT tires though right? What size are they?

 

[adriver]

Quick lube places are like paper routes with a time card.. it's about as low as you can get and technically call it "work experiene" and work history. Oil changes are what the "lot tech/paid interns/the lowest level employee at the dealership" will do when the mechanics don't feel like walking to the next lift to take out the drain plug. I would trust a junkyard mechanic, a tire guy ( when it's about tires), or your self after reading 2 out of 3 confirming threads off a Google search before taking something one of them, who is probaby still in school, and hasn't made it to that section tells you.. If you read this and you're an "oil displacement engineer"..... so-rry.. ??.. ! 3? . (Annnnd done).

 

[Bart Hinder]

Truth to be told you could run the rears at 50-60 psi when you're not towing too. The truck stil has LT tires though right? What size are they?

OEM size, LT245/75R16E.
They're Hankook, which I'm not familiar with, but I'm told they are good. They are new. Aggressive tread pattern. In fact, they may be snow tires since I bought this truck in CO.

 

[swathdiver]

OEM size, LT245/75R16E.
They're Hankook, which I'm not familiar with, but I'm told they are good. They are new. Aggressive tread pattern. In fact, they may be snow tires since I bought this truck in CO.

They're not a bad tire, Korean company with good people here in the states. Well, used to be twenty some years ago anyway when I worked with them.

Yeah, if not towing you can drop them rears down to 60 and maybe 50.

 

[CountryBoy19]

Related tire pressure question: Door sticker says 50psi Front, 80psi Rear.
Right now all four tires have 80psi. (which is what the sidewall says and what Quick Lube did).

Any advice or concerns?

First off, never exceed max pressure of the tire (it will be listed on the sidewall of the tire). The P265/70R17 tires on mine have a max of 44 psi. most LT tires have a max of 80 or there-abouts.

The actual inflation number depends on what you're doing. Is this a family vehicle that has no load 98% of the time? Air the rears up the same as the fronts (50 seems like a reasonable compromise) and then air the rears up to 80 prior to doing any towing.

That being said, a local tire shop (not a quick-lube type place) will be able to run calculations for optimum tire pressure if you can get them axle weight numbers. If you have a grain elevator or stone quarry (pretty much any place that sells/buys bulk commodities/goods by the truck-load) they will have scales. Pull in, go in the office, be pleasant, explain that you need to see what your axle-weights are on your car so the tire shop can calculator optimum tire pressure. As long as they aren't busy they're likely to just let you check weights for free. If you want rear-axle weight with the loaded trailer on it will be a little tricky to get rear-axle only. What you'll likely have to do (assuming the approach to the scale is flat & level) is weigh with the rear axle & the trailer on the scale, then weigh with just the trailer and subtract the trailer weight.

Just to put it in perspective, in my county I will bet there are at least 30 commercial truck scales. All of the limestone quarries & plants, cement plants, agriculture co-ops, feed-stores, etc. As well as some other misc. thrown in. The scales are there, you just have to find them...

 

[JoeM5952]

First off, never exceed max pressure of the tire (it will be listed on the sidewall of the tire). The P265/70R17 tires on mine have a max of 44 psi. most LT tires have a max of 80 or there-abouts.

The actual inflation number depends on what you're doing. Is this a family vehicle that has no load 98% of the time? Air the rears up the same as the fronts (50 seems like a reasonable compromise) and then air the rears up to 80 prior to doing any towing.

That being said, a local tire shop (not a quick-lube type place) will be able to run calculations for optimum tire pressure if you can get them axle weight numbers. If you have a grain elevator or stone quarry (pretty much any place that sells/buys bulk commodities/goods by the truck-load) they will have scales. Pull in, go in the office, be pleasant, explain that you need to see what your axle-weights are on your car so the tire shop can calculator optimum tire pressure. As long as they aren't busy they're likely to just let you check weights for free. If you want rear-axle weight with the loaded trailer on it will be a little tricky to get rear-axle only. What you'll likely have to do (assuming the approach to the scale is flat & level) is weigh with the rear axle & the trailer on the scale, then weigh with just the trailer and subtract the trailer weight.

Just to put it in perspective, in my county I will bet there are at least 30 commercial truck scales. All of the limestone quarries & plants, cement plants, agriculture co-ops, feed-stores, etc. As well as some other misc. thrown in. The scales are there, you just have to find them...

At any truck stop scale just telling them you are doing a military move. I have weighed my truck several times for a military move since they reimburse by weight of goods moved. As a side note I hauled a trailer with cargo weighing in at 9K loaded. Truck did great, just was a bit underpowered going through Wyoming elevation, nothing like moving corner to corner of the country.