I have a 2000 Suburban 4x4 with 235000 on the ODO. The engine (5.3) was replaced with one from a junkyard and I am led to believe that it has about 60,000+- miles on it (two years ago). It burns about a half a quart of oil between oil changes. My gearing is the standard good gas mileage range. That thing is a screamer. I can't plant the gas pedal from a stop or it will just burn up the tires. I use it to tow a travel trailer that, ready to go, I figure weighs about 6,500 pounds. On flat and level highway it's just an average tow-er. Although I have never and never plan to floor the gas pedal with the trailer attached. I pull Black Mountain at 3200 RPMs between 45-50MPH without having to give it but, about half the gas pedal. The only mod to my burb is that when I bought it it had a cold air intake. I replaced the plugs and wires and serviced the transmission oil and filter, and added an additional cooler.

But, I have friends with later model 5.3s that complain that theirs is "sluggish". My buddy has an 07 GMC with the 5.3 and he says it seems to lack power. I have heard from a few people who claim that their GM 1500 whatever with the 5.3 isn't a particularly good tow vehicle. Not everyone to be sure. I do have a friend that has the same model Suburban as me that pulls a bigger travel trailer than mine and says it does well. There seems to be inconsistency in similar vehicles with the 5.3/4L60e package. Of course I would assume that any GM with the gear ratio for towing would pull great. But, I honestly don't see many of those in the 1500 4x4s.

Does your 5.3 pull strong or is it sluggish?

 

Pulls fine for what it is. I know it's not a 6.2 or diesel.
Mine with 135,000 burns at least a quart or two between oil changes. When I hit 50% I have to add a quart.

 

I was talking to a guy that tows with the 6.2. Apparently that's not as good of a towing engine as the 6.0 was/is.

 

The term I hear a lot is "gutless" and that it is. I tow about 5700 up some rolling midwestern hills and my 5.3L screeeeaaams at about 4-5000 RPM when it downshifts. That's actually the main reason I have been in the market for a 2500. I couldn't agree more with your comments about how the 6.0 in the 2500 tows better than the 6.2. That 6.0 is a torque monster.

 

I wonder how the older 5.7 (350) compares when it comes to towing? Just looking at the numbers the 5.3 makes more horsepower but at much higher RPMs. As I understand it the 6.2 was designed to make the Corvette fast more than for torque and towing.

 

the axle ratio makes all the difference. I owned a 6 liter that imo towed better then a first gen Duramax...all due to the rear end.

 

Good point. I'm on the 3.73 with the 4-speed trans