catdoctor

I just purchased a travel trailer 4900 lbs and made our first road trip. Suburban has 5.3 engine & 3:42 rear axle with trailer tow package. Trans in fifth gear my cruising rpm was 2200-2300 rpm. When engine pulled down to 2000 rpm it would shift to fourth. Engine had plenty of power and I could actually accelerate up some hills in fourth or had to let off to maintain speed. I don't like the shift to fourth. Engine revs to 2900-3000 or so. I'm thinking about changing the rear axle ratio to 3:73. I'm almost to the top of most the hills in the interstate when the shifts occurs. My thoughts my cruise rpm would be 2300-2400 but in a better torque band and most of the downshift to fourth would not occur. What are yall thoughts?

kevinkpk

Use the tow button on the gear shift.

catdoctor

Thanks. I used trailer tow mode and put trans in m5. This limited the upshift but would hold trans in m5.

catdoctor

Wouldn't hold trans in m5. sorry.

therewolf

I did the "Great American Road Trip" -(Grand Canyon, Yellowstone, Hoover Dam, Mt Rushmore, Devil's Tower, The Alamo, Petrified Forest,etc)
in 2015, with a Silverado 2500HD-4WD-6.0L- CCLB- (7200LBS) with a camper cap, towing
a 25" Travel Trailer(5800 LBs). It has 342 gears. My overall experience was the drive-train handled it pretty well,
you wanted to stay in low enough gears to keep the revs up on the couple extreme hills of the Rockies, but
the 342 rear handled it exceptionally well, overall. Trailer tow mode didn't help much, I found I had to
manually shift it into the lower gears, to keep revs up, and keep it from overheating.

The one time it did overheat, I left it in drive, and the low RPMs in the higher gear, combined with the workload caused the problem.

intheburbs

Don't waste your money on such a small shift in axle ratios.

Look at the specs on your engine:
Horsepower: 320 hp @ 5400 rpm
Torque: 335 ft-lbs. @ 4000 rpm

Your engine likes to rev. It doesn't make max torque until 4,000 RPM. 2300-2400 is not "a better torque band."
On hilly sections, drive in fourth. You won't hurt anything.
Driving in overdrive puts additional stresses on the transmission, since it has to multiply torque because of the overdrive gear ratio. Fourth gear is over a 1:1 ratio, so it's easier on the transmission.

I just returned from a trip to Yellowstone pulling an 8600-lb trailer. We pulled the trailer over 5000 miles in 2.5 weeks, and I drove the entire time in 4th gear. With the 3.73 gears, the engine was at 3200-3300 at 65 mph.
And this engine has 170,000 miles on it. After the trip, my oil level was exactly where it was when I started.

catdoctor

Thanks, What I learned is the downshift to 4 is ok . It doesn't stay long in 4th. I was chasing something I didn't need to chase.

therewolf

If you are going south out of Utah, avoid that mountain pass with all the warnings at the lookout.
89A near Bitter Springs. There are warning signs 5 to 10 miles before the pass, as well as at the lookout.
Don't try to save time, like I did. If you are pulling a camper, turn back, and take an alternate route.
Just plan to avoid the area. It's an eroded lime-rock road, calling it "gravel" , as the warnings do,
is generous. It's a nerve wracking 5 mile ride, down an eroded, steep grade, and I found myself in the precarious
situation of going slow enough to maintain control of the truck, while trying to go fast enough to keep
the camper behind us stable.

In retrospect, I can now confidently claim that the worst road we will ever drive is safely behind us.

fishing nut

At the beginning of July we put on 2800 miles towing 7000lbs from Wi to the black hills of South Dakota. We did this with 7 people in the Burban as well. We hit the 100,000 mile mark on the trip. Just like in the burbs not a drop of oil used on the 6.0.

tech2

what he said