Will my truck tow safely in the Smokys?

IF you plan on keeping the truck for a few more years while RVing, regearing a couple steps up, like that 3.73, is likely worth it. Probably ought to add additional transmission cooling, too.
BUT, I'd tend to want to try it as is first. Tow with empty or near empty tanks, remove any other excess weight (my wife initially packed our TT like a second home, how many cast iron pans do you need ;). As long as you are under your truck capacities, towing, cargo, GAWR, etc., I expect you'll be fine. If you have to go slow, that's what the extra lanes are for.

^ Totally true statement, but in my experience, the gear splits on the GM 6 speed would be pretty good for 3.08s based on revs and mph with the 3.42s I have.
OP, another way to gain a bit more “power” is to run the absolutely shortest tires you can reasonably run.
If you can size down the tires a size or 2 and still keep the load rating you need , that will get you part ways to where gearing down would.

JIMNLIN wrote:
Is your '17 1500 chevy 5.3 engine 3.08 a 6 or 8 speed tranny.
Either way with the 3.08 gears just drop down another gear and keep the engine in the power band on steep grades.
My wifes '16 1500 chevy 3.42 gears 5.3 engine crew cab 4wd 6 speed tranny does fine for what it is pulling at its 9400 lb tow rating.
A 5k trailer shouldn't be a issue with that model truck even with a 3.08 and a 6 or 8 speed tranny.

The 3.08 is the reason the tow cap is only 6100lbs. You can only down shift so many times before you run out of gears to drop to. Lower rear gears will fix that. There is a reason that Trucks with lower rear gears have higher tow ratings. If there wasn't, all of them would have the same gearing.

Use enough truck and then you can relax.

Did you post your intended route or did I miss it? It may make a difference, tho I agree with the majority that if you are reasonably careful youll be fine.

The rear axle change with a modern six or eight speed transmission would be a waste of money.. If I need more rpms to maintain 50 mph, I simply select 4th gear instead of 5th or 3rd instead of 4th. Absolutely no difference in hill climbing ability. Used to be a big deal with three speed boxes which had widely spaced gears.

The commercials all say that half ton pickups are "rated" to tow at least 10,000 pounds. Go for it. Then come back and ask about LT tires, expensive hitches, and suspension upgrades. There is more to towing than 300hp.

bshack wrote:
What if I changed my axel ratio to a 3.42? Night and day or not worth it?

Night and day would be a stretch, but better is for sure.
It’s not giving up a lot to the Tundra you mentioned, save for gears and about 40? More ponies.
You said axle, singular. If it’s a 2 wheeler, lower gears could be night n day difference and not toooo spendy. But I’d go deeper than the factory 3.42s if I was performing surgery onthe truck anyway.
Regarding how it will tow, the Cascades here are similar in difficulty and altitude as the smokys. I have the same truck as you with 3.42s and have pulled 10k or more (on flatbed) with ZERO issues maintaining speed limit or more uphill. But you gotta let the engine scream.
Take er for a pull and if you don’t like it re-gear or re-truck. But you’ll get there fine as is I bet.

time2roll wrote:

bshack wrote:
What if I changed my axel ratio to a 3.42? Night and day or not worth it?

If you have six or more gear transmission I would not change the rear. You may use 1-2-3 a bit more than 4-5-6 and that is fine.

They had either a 6 or 8 speed transmission in 2017. Both have a really deep 1st gear so that will compensate for the rear end ratio. If you aren't towing in the mountains regularly, I agree...leave it alone. It will get you up the hills with the current rear end you just might be running in a lower transmission gear but the engine RPM won't be drastically different if you put in a different rear end.

But switching rear ends will hurt your MPG in daily driving...which I'm betting is a lot more of your miles.

bshack wrote:
Thanks everyone, I was expecting it was going to come up short. What about a 5.7 crew cab tundra with 9800 lbs towing capacity? Will it handle the grades going up and down with no trouble with the same 5000lb TT? No white knuckles?

A Tundra will pull that weight up and down those hills without breaking a sweat. I’ve done bigger with more weight with ease. Great engine and standard 4.30 gears are good for pulling hills.

I think youll be fine.. Man I got 3:42 with a 4 speed.. I go up blueridge mountains no issues. Mile high campground 5000 feet.. Its just slow for me..

Here I hit start of long grade. 4 speed you dog it in 2nd.

https://live.staticflickr.com/video/39374281641/74c20532ab/1080p.mp4?s=eyJpIjozOTM3NDI4MTY0MSwiZSI6MTU4MDcwMzQ1OSwicyI6IjQyMWQxYjBiZDcyNjQ1YTc5Y2VhNDliMmFjZjllODU1ZjlmMjUyYjYiLCJ2IjoxfQ
Get a big trans cooler installed.. glad I did mine..



and 1st gear 3500 rpm pulling.... and pulling... and pulling...

https://live.staticflickr.com/video/35822079640/5e0bfff2de/1080p.mp4?s=eyJpIjozNTgyMjA3OTY0MCwiZSI6MTU4MDcwMzI0MCwicyI6IjRlZDFhMDI4MThhMWYzOGNiOTU2MzkwOWIwMTQyZjRmNmE1NzYwMjkiLCJ2IjoxfQ