I'm putting 40 in tires on my 2002 ram 1500 with the 5.9 Magnum. I was thinking of putting either 4.56 or 4.88 gears in it. What do you guys think would be better for more power and drivability, not worried so much about gas mileage. Also I'm pretty sure the rear diff is a Chrysler 9.25 12 bolt and it already has a 3.92 but I'm not sure what the front differential size is? And I need to know that to be able to order it. Also does anyone know anyo good websites or name brands that come with a full differential re gear swap with everything needed that's good quality.


Thank you for any help🙏🏻

 

Front will be a dana 44. Neither of those are really designed to deal with 40 inch tires..... Sure, the Jeeps do it, but, they don't weigh 6000 pounds either. But, if you are gonna do it.... the 4.88 gears will be better. 4.56 goes well with the 35's, but, since you are going bigger.... deeper gears are in order.

 

Do you know about how much it should cost to get the new ring and pinion with all new bearings and all that. And how much it would normally cost to get it installed? Also any good recommendations on a brand or place to get them?

 

If memory serves you can't go lower (bigger numerically) than 4.56 in that front case.

 

4.88's are available for the D44.....

As for cost though, likely in the neighborhood of 1500 to 2K for gears/bearings/etc in both axles. Or more..... Depends on labor rates in your area.

 

I was looking at gearing for the front and rear. The Dana 44 is a solid front axle? My truck has IFS?

 

Ooops. Yep. Screwed that one up.

Pull a build sheet for your truck from here. That'll give ya the particulars on the front axle. Prices are looking going to be the same though.... and Magnoom may be correct, and 4.88's aren't available. (and he probably is....)

 

I looked the rear is a corporate 9.25 and the front is a 205 mm HD?

 

Yeah, I am not finding 4.88's for the front..... 4.56 is as good as it gets. 40 inch tires will turn the truck into a dog.

 

oh well, I'll look at the bright side of better gas mileage I guess😭