My ring and pinion are going out on my truck and I was wondering if I got 4.56 rear end does it just go in or do you have to allign the gears or anything like that. Also does anybody have 31in tires and run 4.56. Right now I have 4.10 with 31in but I think 4.56 would be better but Im not sure if it would hurt my gas mileage on the freeway. I usually drive about 75mph on the freeway and keep it at about 2500rpm's. If I got 4.56 I think I would probubly be at like 3krpm's going 75. Would that make a big diffrence on my gas mileage. Thanks for your help

 

Try about 3200rpm at 65 mph. I think you will be closer to gallons per mile instead of mpg. Also if your putting new gears in you need to check and see if you need to add shims.

 

I would have a pro do the gear setup.

 

Ok well if I just put some new 4.10 back in would i have to allign anything. Also does anybody know of a car or truck with 7.5 rear end with 4.10 ring and pinion stock. thanks for the help

 

I just changed my gears from a 3.73 to a 4.56. I had 31"x10.5" tire on it. When I changed the ring and pinion there was a big difference in the amount of torque that I had on my low-end. If you're just concerned about your high-end, you will be spending a little bit more on your gas. That's the sacrifice you pay. But if you're going to be using the vehicle for off-road purposes, then sticking in 4.56's will greatly improve your low-end capabilities. Just know, as you probably already do, you need to make sure that you change both front and back.

One thing that you might want to pay attention to. When you do this, you are changing the amount of stress that is being put on the transmission. You might not have a problem with it at all, but depending on the year, you might want to do some homework as to how much stress there will be and if so, what possible additions you might think about adding. Also, I tried doing the ring and pinion myself and ran into the problem of not being able to get the ring and pinion out. They're pressed on and unless you have a press, there is no way that you'll be able to get that off. To give you a price range...you're looking at about $550.00-$600.00 to get everything set up. These thing are very very technicle and if you mess up the meshing on these things, you might end up wasting precious money on a set that you break in a matter of months. Good luck.

 

Also, you will not have to align anything. When you do the front, you only need to take off the driver side tire (depending on the year). You're not touching anything that would have to do with you're alignment. Keep asking questions though.

 

I think he is talking about alighing the gears not the whole truck.

 

If you're talking about aligning the gears, don't even worry about that. It's not even aligning them anyways, it's meshing them. Look, you don't even need to worry about that because you're not the one that's going to be doing it. It's the money and the hypothetical problems that you might face afterwards.