Afraid to Ask 3.08 verses 3.42 towing 5,560 #'s UVW

2017Silverado · March 18, 2018

I have a 2017 4x4 z-71 5.3 Double Cab. I got to looking at my window sticker and it shows that my rear end is a 3.08 not 3.42. I am wanting to buy a Travel Trailer that has Unloaded Weight of 5,560# with a Dry Hitch Weight of 560# and a Gross Vehicle Weight of 7,250#... Am I going to be in a pickle when I go to travel? I will be going up and down hills here in California..........

Thanks for your time

ember1205 · March 19, 2018

You're not going to want to tow that trailer...

4x4 Double Cab with the 3.08 rear end is rated to tow 6200 lbs and has a cargo rating of 1800 lbs. By time you add in all of your "stuff" and the weight of the passengers in the vehicle, you're not going to be able to distribute things to get to where you need to be.

Loaded properly, your trailer would literally max out 6200 lbs. And, with proper balance, you'd be looking at somewhere around 800 lbs or so of tongue weight. Two adults is about 350-400 pounds on average, leaving you with about 600 pounds of leeway for additional cargo in the bed (which would impact how much tongue weight you could carry without a weight distributing hitch) and passengers. You'd literally be right on the line.

That truck is going to drag badly in hilly areas weighted down like that to the point where A) your MPG is going to be well into the single digits, B) you're going to tick off a LOT of people by climbing hills so slowly, and C) you're going to feel wiped out when you get where you're going. The longer the distance you drag that trailer to get where you're going (or home), the more that this is going to ring true.

Jon A · March 19, 2018

Budget for a gearswap and you'll be fine. If you have a 6-speed I'd go 4.10's, if you have an 8-speed either 3.42's or 3.73's will work. First, of course, verify what you have--window stickers list standard and optional equipment and will sometimes list two different things in different columns so verify that before going through with the gear swap.

2017Silverado · March 19, 2018

Any idea on what a gear swap would cost? There is no way I can swap the whole truck. We just bought it and at the time we were giving up camping all together. But we have changed our minds and really want to get back into it........

Thanks for the postings

muddkatt · March 19, 2018

2 hours ago, 2017Silverado said:

Any idea on what a gear swap would cost? There is no way I can swap the whole truck. We just bought it and at the time we were giving up camping all together. But we have changed our minds and really want to get back into it........

Thanks for the postings

About $1400.00 for a 2WD, no idea being you have 4x4

2017Silverado · March 20, 2018

Well bummer, so I have changed the trailer that work for both of us, dry it weighs 3,936 which is about a 1,400 Lbs lighter, and is very doable as far as trailers go. Not the quality we wanted but we don't really plan on doing the intents traveling we have done in the past.

Swerd · March 20, 2018

I have a 2015 crew cab with the 3.08 as well. I tow a travel trailer that has a dry weight of 3500 and it pulls it just fine. That being said, I would not want to go much heavier because it does struggle a little bit climbing.

2017Silverado · March 21, 2018

9 hours ago, Swerd said:

I have a 2015 crew cab with the 3.08 as well. I tow a travel trailer that has a dry weight of 3500 and it pulls it just fine. That being said, I would not want to go much heavier because it does struggle a little bit climbing.

Thanks....... For your post

Cowpie · April 1, 2018

On 3/18/2018 at 10:55 PM, Jon A said:

Budget for a gearswap and you'll be fine. If you have a 6-speed I'd go 4.10's, if you have an 8-speed either 3.42's or 3.73's will work. First, of course, verify what you have--window stickers list standard and optional equipment and will sometimes list two different things in different columns so verify that before going through with the gear swap.

I would go with 4.10 either way. The top gear ratios of the 8 and the 6 are almost the same. The only major difference between the 8 and the 6 is the bottom gear ratio and the steps between the gears on the way up. 4.10 would be the cat's meow either way.

2017HD · April 4, 2018

A couple more items to consider - I did a gear change on an old S10 back in the 80's and it was just under 1k to go from 3.08 to 3.73 which was the largest I could go without changing housings - I suspect that here the best you could do is 3.42 as the 3.73 comes only in the NHT HD Towing Pkg. and it is in a different axle housing. Also changing diff gears on a 4x4 means doing both of them - it also means new seals and bearings and you need to find a person who knows about how to set the lash on the gears - it is an art. As others have suggested - make sure that the diffs are indeed 3.08 - double check the options list - sometimes a gear change is part of a tow package or just on its own.

Remember that your Tow Rating includes all of the Payload - which is around 1800 lbs. As others have said the 3.08 is good for a total towing of 6200 lbs A trailer of that size should have a tongue wt around 800lbs (closer to 1000 lbs with batteries ,LPG, and whatever you put into the front cubbies). So with a 6200lb trailer you would have around 800lbs for you and your passengers and cargo.

I have towed a 5800 lb tt with a 99 Tahoe and it was no fun - yes I know the 5.3 makes more HP and Torque than the 5.7 in that rig and the 6 spd is better than that old 4 spd - but that rig was a real dog to drive both on the flats and in the mountains here in Oregon. I did have a huge improvement when I went to a 2500HD 6L 6 spd 4.10 gears. My advice is to scale back your trailer to something in the 4500 lb Dry Wt range (remember until you weigh it you are not sure how much it weighs).

Even then I would be prepared to gear down for the hills - that engine loves to rev in the 3500-4000RPM range to make the best HP and Torque balance. Taller rear end gears would allow you to use a higher transmission gear and still maintain 50-55 MPH. With the smaller rear gears you are probably going to have to use lower gears to get the RPMs up and you will be going slower.

Good Luck

Donstar · April 14, 2018

On 3/20/2018 at 9:52 AM, 2017Silverado said:

Well bummer, so I have changed the trailer that work for both of us, dry it weighs 3,936 which is about a 1,400 Lbs lighter, and is very doable as far as trailers go. Not the quality we wanted but we don't really plan on doing the intents traveling we have done in the past.

Good solution. What did you end up buying?

2017Silverado · April 14, 2018

6 hours ago, Donstar said:

Good solution. What did you end up buying?

Have not bought anything yet. I am looking at a Lance 1985 or 1995 Dry Weight is around 4100 on either one......

I went to my dealer and got a cost of $4,000.00 to so both front and rear gear change and we were going to bite the bullet and do it, but it turns out that GM will NOT support it and it will void my warranty......... But you know it's OK with them not supporting it it will push me to buying FORD when I am ready for a new truck. I have been a GM guy for well over 40yrs and I am very disappointed they will not support the change. (They refused to give my dealer the codes to change the speedometer and odometer) To be honest my salesman and the Service Manager were also very upset over the whole thing.....

Donstar · April 15, 2018

Personally, I would not do a gear swap or major performance modification on such a new vehicle. Warranty will be up before you know it and by that time you will know if your truck is a long term keeper. I went to a local RV show yesterday and bought a Winnebago travel trailer to pull with my V6. There are many, many trailers out there within your load range. You spend over 95% of your driving time unhitched so why "modify" your vehicle unnecessarily?

KARNUT · April 15, 2018

It seems the answer is to buy within your trucks capabilities. There’s plenty of light weights to choose from. I’m in the fifth wheel camp myself and have seen half tons with those.

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Yonah_Mtn · April 15, 2018

I towed a 29'-6" about 6K# dry with a '10 Silverado, extended cab, 4WD, 3.42 and auto with no problems.. Put it in tow mode, set the cruise and let it do what GM built it to do.. Tow mode is just as useful coming down a grade as it is going up. I lived in western NC at the time and it is mountainous.

https://en.wikipedia.org/wiki/Interstate_26#North_Carolina

We'd used to go up the mountain, then West on I-40 to Tennessee.

When I had the camper I used to frequent the camper forums, the 4.10 uses a lot of gas as a daily driver.

I'd go with the 3.42 and if your truck lacks the transmission and engine oil coolers, I'd add them. Inside your glove box, there's a decal with all the standard and optional equipment. The decal will have what weight the truck is designed to tow.

I spent 45 years in power train design engineering, engines, transmissions and differentials; my last 11 years was in forced induction design engineering. IMO, 3.08s are a bit too low numerically for good towing.

Have you looked into what they call ultra light campers? The ultra light version of what I had was in the mid-3s dry..