T600 Specs.
 

What would be the best specs for fuel efficiency for a 2002 KW T600?

depends on where you run and how much weight you're pulling.

Flatbed. Steel coils and lumber. Not sure of the weight though. Will be running midwest. Thanks for your help.

Heavy loads but no hills.
If you want to drive 60 mph, I'd say an 11-ish litre engine, 13 speed, 4.11 rear, 24.5" rims.

I own a T600 with a 3406E CAT w/a Super 10. I don't remember the rears, but would estimate they are around 3:35 or 3:55. I have been getting around 6.91 mpg lately.

if you're hauling steel or lumber, you will always be close to 48000#. in that respect i would spec an ISX or such with about 450 hp 1650 tq, 13 spd, 3.55 gears and 22.5 lo-pro's. the 13 spd will let you split the upper end and 1650# of torque will let you keep it under 1500rpm to help with fuel economy. just my .02 :)

Thanks for all of your replys. This information is very helpful. You all have a safe week.

Absolute best specs?

10 speed direct drive
2.64:1 rear gears
super singles

What kind of MPG are you all getting?

a lot depends on driving habits and load and weather [headwind :x]. also engines play a part. newer engines tend to be more efficient due to better electronics. i guess what i'm trying to say is that it's hard to compare mpg's. i've had a low of 4.4 mpg's :sad: and up to 7.8 mpg's. :D like i said, it depends. 8)

I have a 2006 T600 w/ 500 ISX, 13spd, 24.5's, 3.70 rears. Running 75mpg under 78,000lbs I got 4.85 the other day. I backed it down past Texas and got 6.2mpg. How you drive it depends on what mpg you get out of it.

I also have a flat top 84" bunk (no roof fairing) pulling a tri-axle moving van.