question on nose

[djordan1184]

I new 06 6L. 38" tires. Ihave not changed the gears in my rears yet.when I'm doing about 70 and let off of the excell a little bit and let the truck cost some
it makes a noise that sounds like gears are working a little to hard kind of a little off balance feel if you can understand what i mean.Its hard to explain,but it only does it for a couple seconds then goes away.but if I go faster than 70 it does it more.Does this have to do with me not changing gears yet?I'm thinking transfer case working overtime.does anyone have any oppinion on this

[djordan1184]

does anyone have any suggetions on what this could be?

[Ranger429]

It should not make any difference without changing the gears and going to a taller tire other than it will be slower off the line. I don't know exact #'s but you basically lowered your gear ratio by putting the taller tire on. I don't have the gear calculator but you would need to change out to possibly a 4.56 or 4.88 gear ratio to get it back into stock configuration. Stock gear ratio should be a 3.73 in your truck. If anything at 70MPH your transfer case would be working less.