Upgrading our Tow Vehicle/ 8100 Vortec

[blucloud]

I am in the process of uprading our tow vehicle. the vehicle we are considering is the GMC 2500HD, 4x4, crew cab. I am interested in the 8100 Vortec w/ the Allison 6 speed and 410 gears as a drive train. Are there any forum members who tow with the 8100 Vortec that could give their opinions of this motor.
Decisions..decisions...Dave

DUH! We will be towing a 25ft sovereign.

I tow with the 8.1L in my 2001 Suburban. I love it. It has tons of power. Towing a 31' Sovereign you forget it's back there.

[Airstream25]

Originally Posted by blucloud

Are there any forum members who tow with the 8100 Vortec that could give their opinions of this motor.
Decisions..decisions...Dave
DUH! We will be towing a 25ft sovereign.

Dave,
I have the 8100 Vortec in a Yukon XL. This engine is a nice improvement in towing power compared to the previous 5.3 L.

I have gotten 9.3 mpg highway towing about 55-60 mph.

On another trip at 75 mph and a head wind, the mileage dropped to 7.5 mpg.
I have a 25' Excella. I do not have the Allison transmission.

[j54mark]

I'd give some consideration to a lower rear end ratio than the 4:10 unless you are really going to be loaded down. The 8.1 has a pretty strong torque curve.

On a related topic, I just had my '04 K2500 crew cab in for an oil change at 37,000 miles (the dealer does oil and filter changes for $14 for life!) and have yet to have a single item fail in any way on mine.

Mark

[davidz71]

I have a little over 50,000 miles on my '01 2500hd extended cab 4X4 with 8.1 and 5 speed Allison auto transmission. It has the 3.37 rear end. I've only had an AC vent replaced under warranty because one of the vanes kept falling out when I went to adjust it up or down. I did have the battery case start leaking at the positive post but that is not unusual for side post batteries. It was replaced and no problems since. The transmission actually would not shift into reverse for a few seconds due to the corrosion inside the battery cable cap.

I use to tow a '77 Excella 500 31' but now tow an '86 Sovereign 25' model. Both are a breeze to tow with my truck. While performance is just great, if I had to do it all over again, I would choose the 4.10 rear end and go with slightly taller tires than the LT245-75-16. Even an LT265-75-16 E rated tire would make the truck look better and bring the overall ratio comparable to something like a 3.90. Of course, you would need a programmer or device to recalibrate the speedometer but the combination would look and perform fine. If you don't think you will ever go to a taller tire, the 3.73 rear end works fine. I get 10-11 mpg towing and I have broken 15 mpg on the highway a number of times without AC and driving 68 mph.

[wrepete]

Dave, I'm towing with the 8.1 in a 2004 Chevy Avalanche 2500 into high mountains in Wyoming and Montana the past two summers, and there is no lack of power or towing comfort. I've had three 3/4 ton Suburbans over many years, and I liked them a lot, but I really like the Avalanche with the rear covered bed. You will like the big V8!

[Silvertwinkie]

I tow with at 6.0L w/4.10s and I do great with our 25'. You'll be in great shape with that TV. Just watch the oil levels. I've heard many an 8.1L owner say it is not uncommon to eat up to 1 quart in between every oil change.

[AgZep]

We have a Silverado 2500HD with the 8.1 and the Allison. I forget the gear ratio, but I think it's the 3.37.

Since gas prices hit the roof in August, we've been driving at 55. Often, we reach 12mpg towing, and we even broke 14 a few times. Unladen, on a long trip between southern New Mexico and northern Colorado, we were over 17 mpg. I would never have believed that possible...

The 8.1 is certainly a great motor for towing, but I have to say it's the Allison transmission that is really exceptional. I've never seen the tranny temp gauge get high, even towing uphill on the hottest summer days. When descending steep grades, you just brake to your desired speed, take your feet off the pedals, and let the Allison hold you right at that speed. It's wonderful.

I always tow with the cruise control and the tow mode engaged. No problems.

[dwightdi]

We have the 8.1 in a 2001 quad cab dually with 4.1 rear end. Before I bought the truck they had replaced the engine with a crate engine because the original engine burned oil badly. I have 35000 on the truck now and put $1000 in it two months ago to replace the fuel pump and the spark timer sensor. Truck, of course, has lots of power and will pass anything on the road except a gas station. Pull a 31 footer. Have the allison transmission which runs great but the Chevy tech bulleton says I should have reprogramed to change the downshift set points. Something about possibly over reving the engine under some conditions.