My '95 GMC Sierra 2500

Greg

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Admin
Oh, my 300 mile drive to Telluride and back netted me 15 MPG, which is pretty good for a 3/4 ton 6.0 truck! My '02 averaged 12 MPG. I think much of that mileage was due to the roads down & back, 55 - 65 MPH and no freeway driving. I'm hoping the 6 speed trans is part of that too, keeping the engine from revving too high and consuming much fuel. We will see this upcoming week, I'll be putting 400-500 miles on it with half of that being freeway driving.
 

Greg

Are you not entertained?!
Admin
Been driving the 2011 GMC for work and it's been great, I feel safer driving a bigger truck on the bad roads up in the mountains. I've been getting 13-14 MPG and just over 400 miles per tankful with my driving to work. I'd still like to replace the tires with KO2's, eventually. I really like how the 6L90E transmission works, even with over 250k miles it seems to be very well built.

I did get rid of the Flowmaster muffler, it was a 40 Series (pretty small) and just way too loud. I replaced it with a large 3.5" Magnaflow muffler (part # 12909) and it's much better, no ear-piercing resonation in the cab and much quieter, but still louder than stock.






I was able to tow with the truck over the weekend, taking the Willys out to Green River. The truck managed 11 MPG towing, which isn't bad IMO! The truck tows very well, plenty of power and very stable. The 6 speed trans seems to have a much better time towing than the previous trucks 4L80E, it'll drop a gear or 2 on big hills and get back up to speed, then settle down on the flats to low RPM's.

 
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