A 2008 2500 chevy 4 door 4x4 pickup 35 inch tires, 6L gets 8 mph. My stock 2004 6L gets 12 around town. Much better on the freeway (14-16). I weigh a lot more then the puckup! 8.400, compared to maybe 5,000. I'm carring a winch, rubberduck complete UPC, rear tire carrier, SMA brush guard, plus... the pickup none of thoses things. One thing I can do that he can't do is unlock the transfer case and make it passive, but still limitive 4 wheel drive. Anymore ideas why? He has 4.10s.
