3.42 Vs 3.73 Gear Ratio

Maguillacutty · February 9, 2008

Wondering what you all thought on the two or which is better to have. I currently bought a 2007 GMC Sierra Z71 5.3 it has the 3.42 gear ration.

Also would anyone know if the 5.3 V8 flex fuel has the same power etc as a regular 5.3 V8??? This is new to me..

thecraft · February 9, 2008

Depends on what you want to do with the truck, and what size of tires you are running. Assuming you're using stock size tires, 3.73 is probably the best all-around ratio. 3.42 is better for MPG if you do highway driving, while 4.10 will be much better if you tow often.

Tylerz71 · February 11, 2008

I think that a 3:73 is ike the minumum, at least for me. My 33's do allright with my 5.3 with 3:73. but i am glad i dont have 3:42's. If I were to ever go over 33" tires, i would re-gear to at least 4:10.

thecraft · February 11, 2008

I think that a 3:73 is ike the minumum, at least for me. My 33's do allright with my 5.3 with 3:73. but i am glad i dont have 3:42's. If I were to ever go over 33" tires, i would re-gear to at least 4:10.

Yeah, I wouldn't run anything over 30" with 3.42 gears.

onac255 · February 12, 2008

Im running 265/70/17 bridgestone duelers with the 3.42 gears and she really is a dog off the line. But then again i can get 21-23 MPG on the highway. I really wish I had 3.73s

dietz4ibanez · February 12, 2008

3.73 is the way to go!

black jack · February 13, 2008

I had an 02 z71 chevy avalanche and it had the 3:75 rear loved it never got me stuck in mud, sugar sand and in rain never spun the tires, gas miles was around 21 highway. Now I have an 05 Z71 chevy avalanche with the 3:42. lets just say wish i still had my 02. I had the the 3:42tires spin in the rain and even gravel. gas miles Im getting 18-20. which is strange because my 02 was heaver than the 05.

thecraft · February 13, 2008

I had an 02 z71 chevy avalanche and it had the 3:75 rear loved it never got me stuck in mud, sugar sand and in rain never spun the tires, gas miles was around 21 highway. Now I have an 05 Z71 chevy avalanche with the 3:42. lets just say wish i still had my 02. I had the the 3:42tires spin in the rain and even gravel. gas miles Im getting 18-20. which is strange because my 02 was heaver than the 05.

Uh... a different gear ratio won't cause the bad traction you're describing. Your old truck might have had better tires or a locking rear differential. Going from 3.73 to 3.42 won't cause that.

Maguillacutty · February 14, 2008

I hope somebody can help with my confusion here. Does anybody know why some of the Z71's have the 3.73 and some have the 3.42? My new truck came with the towing package and has the 3.42 gear ratio. Is it gonna bog me down Willie?? Will I feel a considerable difference between the too.

I have a 2001 chevy Z71 with the 3.73 gear ratio.. My new truck GMC 2007 Z71 classic ext cab has the 3.42 most important.. Would it be ok for me to switch them?? Both have the 5.3 V8