[535banshee]

power is not a problem with 35's and a my bully dog but it is when you have 11000lbs behind it. its just not like it was when you are tring to take off. its a big differance that i thought there was something wrong with the truck at first. changing the gears should get me back to where it was before.

 

[StillTooSlow]

I think you screwed up a bit on your math. The ratio of 6th has nothing to do with 5th. 6th is 0.62x4th RPM. No?

i see you have a 5.9 i have 6.7 with a six speed. the gear ratio is way different. the 68re is 1:1 in forth gear and .81 for fifth and .62 in sixth. all tire to gear charts are for 1:1 at 65mph. my tire size with 4.56 is 2852rpm's @1:1
then take 2852 x .81= 2310 in fifth
2310 x .62=1432rpm's in sixth at 65mph

stock is [email protected] 1:1 @65mph
2715 x .81= 2199rpm fifth gear
2199 x .62= 1363rpm in fifth @65mph

69rpm diff

 

[535banshee]

good point. you might be right? i will check and see.