I currently have 37's on my truck with 4.56 gears and a stock 4.6 motor. When I went from 3.55 to 4.56 gears I expected a big gain in the torque. I didn't notice much at all. I believe some of the problem may be the set up of the gears. My buddy, who work at a local ford dealership for 5 years, installed the gears for me. Right away I noticed how loud the gears were. I can actually hear them over the radio. When I drive the truck it just seems likes it's being held back. Since I'm tearing it apart I figured I will switch the gears again to 5.13. I just wanted to see if anybody is running this setup. I know most install 4.88 gears, but I don't drive the truck much so I am not worried about gas mileage.

 

are you 4x4? i dont think you can fit 5.13's in the 8.8 front end.

 

yes it is a 4x4. If the gears don't fit I guess I will be going with 4.88. I saw Yukon made reverse cut gears for an 8.8 so I just figured they would work.

 

well give it a shot, my 4.88's were a tight fit.

 

I wouldn't think going from 4.56 to 4.88 wouldn't be enough to notice. I have 4.56s and 35s, and I'm really happy with them. I get 16mpg city and highway. Maybe there's something else going on if you couldn't tell a difference between 3.55s and 4.56s

 

Agreed. There wouldnt really be a noticeable difference. I've got 33's w/ 4.56's and love it. I do have a loud gear whine too. I think part of it is the ratio which gives you less tooth contact and the other part is I didnt pay the extra $75 for name brand gears. The installer opened up the pumpkin twice after the original install to ensure a perfect wear pattern too. He told me he put 5.13's in a jeep the week before that had no whine to them, which leads me to believe it has something to do with the brand of gears.

IMO take the money you would be spending on new gears and buy some LT headers or something.

 

I don't know if my gears whine or not. I got my mud grapplers put on the same day I put my truck back together with the 4.56s installed, so I doubt I could hear the gears over the tires

 

thanks for the input. I am going to tear the rear apart to double check the wear pattern to make sure the setup was done right. If it was, I will probably let it go. If not, new gears will be ordered.

 

find anything out?