Hi all. Been lurking for a while, finally joined and have a question. I've gotta buy a Sub and prefer to get a 2500 for the good parts. The 6.0 gives me pause and has me seriously considering the '92-'99s where I can get a 2500 with a 5.7. Is the 13 mpg Hwy with the 6.0 the best it will do in a 2wd 2500? I drive gently and don't usually push over 70 mph and it seems like 17-18 is what I should expect in the 5.7 equipped earlier models. The 4L60 and crummy rear axle in the 1500s is what is pushing me towards a 2500, I don't need it for HD towing (flat towing my CJ7 about max),I just want a solid drivetrain. I've tried using the search function to answer this but, no luck.

 

You could do better than 13, maybe 15 highway only (driving ~60), but not much better than that while the truck is still stock.
Friend has a 6.0 (I've got 5.3), and said that swapping to the electric fans can buy you 1-1.5mpg. If you're not towing heavy loads, that should be a reasonable change. Also, intake and/or exhaust can bump you a bit as well... All said and done you could possibly get up to 17, but for a good bit of work to get there.
Other option would be to simply buy a 1/2 ton with the 5.3 and swap the axle/trans if/when needed... upgrade when it needs the parts, if you're really only towing a CJ7, the 1/2 ton should work fine if taken care of.
Just my $0.02, best of luck with whatever you pick!

 

I just bought a used 2001 2500 6.0L 4x4. I have not put allot of miles on it yet but to and from work I averaged 13.3 with 60% hwy usage. I did a hunting trip 2 weeks ago and drove 150 miles highway only. Exception was roughly 2-3 miles on and off filling up and refill at destination. I got 14.6 MPG on highway and I drove at 72MPH on cruise - all stock with 128K. Hope that helps. I think 15-17 is possible with some mods and possibly lower speeds. Also a side note - my truck has 3.73 gears not the 4:10's.

 

Thanks for the replies guys. I bought a 7.3 Excursion Friday. At 70 she got just a hair over 19 MPG average in the TN and AL hills. Once we hit the FL flatlands at the same speed, she returned just a tick under 21 MPG.

 

Calculated or vehicle display?

 

Both, they were pretty close but with a 44 gallon tank I figure there's a decent margin of error when filling/topping off the tank due to foaming and vehicle angles