I saw a post on here of somebody with a truck that has a 4 speed transmission, 33 x 12.50s, and 4.10 gears. I have the same setup except I have 3.55 gears. I don't remeber the users name and I am hoping he or someone else that has a truck set up like that will come across this. I was wandering how well the truck did on the street and what RPMs the engine is turning at 60 in 4th. My truck isn't a daily driver.

Also, from what I have seen, the Dana 44 front axle has a 3.54 gear, while the rear is 3.55. Am I correct in this? I know that isn't much of a difference, but it is different; seems like it would cause problems.

 

3.54 vs 3.55 is a mathematical rounding difference and is insignificant. Ring and pinion gears have various numbers of teeth. The 3.54 can have 39/11 teeth or 46/13 teeth (ring/pinion ratio). 39 divided by 11 = 3.545454... so when you round it up it is 3.55 and if you round it down it is 3.54. Using 46/13 you get a ratio of 3.53846 which they round to 3.54.

The reason that you can mix the two and not cause a problem is because you are not supposed to use both front and rear differentials (4x4) at the same time in good traction conditions. Poor traction conditions allows some slight give and difference.

 

http://www.grimmjeeper.com/gears.html

Play with this ^^^ to tell you what rpm you should be running at which speed. Just enter your tire size, transmission, and gear ratio correctly. Transfer case shouldn't matter for this application. The chart on the very bottom is speed in MPH vs RPM.

 

Thanks for the link wontacceptthis.