bhall97-150

is this a good idea or bad? what kind of gas milage can i expect? also will this wear out my transmission and engine?

bchauler

I have been running 265/75/16 tires with 3.31 gears and I think it contributed to the demise of my trans last summer. I replaced my rearend with a 3.55 diff to get my ratio back closer to stock and the truck seems to shift better. Also, I was getting some tc lockup shudder that seems to have vanished since the swap.

bhall97-150

so shuld i not do it? i can't really change my gears the same time i swap tires

bchauler

I don't know. 29" to 33.5" is a big jump and 3.08 is NOT a good ratio for much but flat highway cruising. I would be concerned about the effect on the trans for sure.

Swapping a diff isn't that hard. I did it in my driveway with hand tools in maybe 5 hours, and I'm not very capable or bright. I bought mine at a yard for $60.

bhall97-150

so looks like on my door sticker i have the h9 axle and that is a 3.75 but the vin decoder says i have a 3.08? I'm guessing the sticker is correct??

greenheadkiller98

Horrible idea. I had a 4.6 auto with 3.55 and 285 and hated the power loss

greenheadkiller98

H9 is 3.55 limited slip.

bhall97-150

i might go with 275/75

BlackThundah

I had 285 75 16 on my old reg cab. It had the 4.2 with 3:08s. I had it like that for 4.5 years before I sold it and never had a problem. There was a noticeable loss of power, but nothing unbearable. It never affected my tranny at all.

bhall97-150

ok it all depends on if i keep my old tires and rims for long drives to save gas.