Gear Question

Anthonyb · June 28, 2010

I have the opportunity to buy a set of gears for $45. I want to lower from my stock 3:73 to 4:10. They are listed as coming out of a 14bolt Gm rear end. I have a 2008 2500HD 6.0 with the 6l90 and the G80 rear end. Will these fit in my truck? This seems like a good price or is this the going rate for used gears?

markw8 · June 28, 2010

I can't answer your question but would like to know your reason for wanting to change. There is so much difference in ratios from the 4-80 to the 6-90 it would seem there is no real benefit. First gear is lower and 5th the first OD ratio isn't as deep as the 4-80.

Mark

Matt_ · June 28, 2010

IMO, Never buy used gears unless its for a beater/offroad rig. Your chances of having noise issues are near definite, you dont know if they were properly installed/broken in/cared for in the previous truck.

gear swaps are too time consuming to try saving $100 on the r&p... get a new gear set...

Anthonyb · June 28, 2010

Thanks Matt, that is good advice and I will do that. I hadn't considered the potential for noise or even reliabilty issues. BTW, yours is one of the best looking trucks on this forum. IMO.

Mark, I went up in size on my tires and now at 60 mph I am at 1,541 rpm's and it downshift shifts with very little acceleration and the slightes grade. 4:11's would get me to 1,698 rpms where as 1,654 was what it was with stock tires. I really think I want to find some 4:30's but am not sure if they even make that gear. 4:30's would get me to 1,776 rpms. This is all based on .67 trans gear ratio, 6th gear. 4:56 is lower than I want to go. Any suggestions on the best place to buy gears that are quality?

markw8 · June 29, 2010

Thanks Matt, that is good advice and I will do that. I hadn't considered the potential for noise or even reliabilty issues. BTW, yours is one of the best looking trucks on this forum. IMO.

Mark, I went up in size on my tires and now at 60 mph I am at 1,541 rpm's and it downshift shifts with very little acceleration and the slightes grade. 4:11's would get me to 1,698 rpms where as 1,654 was what it was with stock tires. I really think I want to find some 4:30's but am not sure if they even make that gear. 4:30's would get me to 1,776 rpms. This is all based on .67 trans gear ratio, 6th gear. 4:56 is lower than I want to go. Any suggestions on the best place to buy gears that are quality?

Ok, was just wondering.

Mark