Techman,

Yup. We pull our PQ 280 with a 2010 Avalanche w/ the 5.3. The problem we've got is that it was built with the highest axle ratio Chevy offered, which wasn't even supposed to be available in the 4WD trucks; it's blocked out in the owner's manual on the towing capacity chart. It was obviously special ordered as a non-working wannabe Cadillac (it's the LTZ), and does, indeed, make for a great daily driver. It didn't even have the OEM auxiliary transmission cooler, which I had installed to pull our previous boat (5100 lbs, boat and trailer). When we started pulling our PQ, at 7000lbs, I added an aftermarket transmission cooler, with a thermostat-controlled fan, that seemed to resolve MOST of the transmission temperature issues. But it still struggles with inclines, and I am constantly notified by the war dept that the engine is running really hard. I just tell her it's fine and running well within the RPM range it was designed to run. I try not to punish it too much, and allow it to slow down as we climb. Still, though, the climb up the "cut-in-the-hill" going south from the Ohio River has us trying to stay out of the truckers' way.

Thanks. Brad.
(937)545-8991

Going from gas to diesel was a revelation as many have said when it comes to towing. My 8.1 ran around 3200 RPM's at max weight running level on the highway 65-70 mph. The same load with the diesel is around 1500 RPM barely breaking a sweat.

Apologizes to the OP for the side tracking...but at least some flavor for different experiences. Diesels are the king of towing but properly equipped gas trucks can tow just fine within their towing limits.

Hey Brad, what gear ratio do you have in it? I have the exact same truck.with 3:42 gears and was thinking of finding some 4:10 geared axles out of a suburban or caddy escalade (RPO CODE GT5) and doing a swap. Ive pulled my buddy's 28 Cig SS and the truck felt every pound of it! Felt like i was driving with the e-brake on! Never got hot or anything just felt hindered and i was thinking of gearing up a bit. :)

Couple things, towing with that 5.3L gas I would think has to be work, that is a small motor.

On the Diesel running at a lower rpm true, but what is the redline? My point is what percentage of redline is it compared to a gas motor at 3000, that has a redline of 6,000? Don't get me wrong,the Diesel is hands down better but we are talking the OP has a small 6,000LB boat and trailer.

Ron Forbus that used to be on here currently tows a 39 NorTech with a gas Tundra!.

As far as the OP goes.....i have been looking at turbos for some time now...just dont have the time to pull the trigger on one just yet....depending on what year your turck is you will probably have to modify a basic kit to fit your application...i have been looking at the Trick performance turbo kits or the On3Performance stuff...

Was that 8.1 with an Allison or a 4L80E? That's a lot of rpm for that speed, even with 4.10s. My 2002 8.1/Ally at 70 is 2000 rpm.

From the OP
Gas engines make their torque at high RPM's, just the nature of the beast. Mod's to his motor will make more power but the power curve will not change that much so it will still be a screamer just making more HP. Yes, diesels have a much narrower powerband but when you make all your torque down low you don't need to spin it that fast. I found some people just more sensitive to higher RPM operation. (my wife included) It's just noise and you aren't hurting a well maintained motor as long as it isn't overheating.

Tune into the Gauntlet series from TFL (YouTube) They take stock trucks on torture test tow runs for miles at redline. Modern gas trucks just roll with it....at single digit MPG's. Fun.

4L80E, tow haul mode engaged towing 13K lbs.

Wally,

3.10. Like I said, if you look in the manual, the chart that gives you towing capacities for the various axle ratios has that block X'd out. Talking to the service guy at our local dealership, he tells me it shouldn't have even been an option to order; 4WD/3.10. Don't know....

I've looked into swapping gears myself, and all the transmission shops suggest swapping the axles entirely, as shimming gears is not for the layman and the labor to have them do it is pretty cost prohibitive for me. An axle swap is something I can do myself with some strong-backed help, and they can be found pretty affordably.

I can definitely tell the boat is back there, but the only problematic aspect is climbing hills. The truck handles the load well, as far as control and stopping. If I understand correctly, the Avalanche is built on the Suburban platform, so the control aspect is understandable. I very often find myself at 75+ on flat highway and never have a concern about controlling the boat.

I'm pretty happy with the truck, overall. It's a great daily driver. It gets decent milage, due to that axle ratio, and it rides pretty nice, being the LTZ. I have a buddy that has a, F-250 PSD, and I feel like I'm going to be passing blood for a week if we take anything resembling a long trip in it.

Thanks. Brad.
(937)545-8991

Got it, makes sense now.