Differential ratios & changing

Hi, this is a very interesting and informative forum with plenty of knowledgable people some of which I'm sure can answer my questions or point me in the right direction.

1) When changing the gear ratio you obviously change your pulling power and fuel consumption. Where can I find statistics that would show the results of changing from one ratio to another?

2) How do you change the gear ratio? Do you have to replace the whole rear end including the axles or is just a matter of changing the gears in the differential?

Thanks

I dunno of any such charts with statistics but in general lower gears=more power and less mpg. All you need to do is get a different ring and pinion, and also a new gasket set might not be a bad idea. But what are you gonna be using the truck for and what year/model/engine/?

Thanks, that sounds easy. The truck is a 95 Sierra with a 5.7 and I think 3:73 diff. I just bought the truck and am planning on putting a 9.5 foot camper on it and hauling my motorcycle and atv to the mountains.

I'd say you should prolly try it a few times with the 3.73's and see what you think first. thats what my truck has and i pull skid loaders and tractors with it with no problems. 4.10 wouldnt make to much difference in mpg but would give you more low end grunt to get a rig moving from a stop or more power accelerating up a hill. But i suggest you try it as is first.

this is not an easy job. you have to change both front and rear. then you have to do some shim testing to get the ring & pinion to mate perfect
unless you have done this befor I would take it to a shop and have it done. I agree try it with the stock gears first.