I have a 2003 Hemi 4x4 with the 3.92 gears and am thinking about going with the 4.56 gears. For those of you who have already done so how does the switch affect things like mpg, citydrivin, and highway driving. How much did the gears cost to buy and how much to install? And finally are you happy with the upgrade? Why / Why not? Any feedback would be greatly appreciated. Thank you.

 

very un-highway gears, your gas mileage will goto ****...er. haha. Its definantly kickass for racing though. I got 3.73's and my truck is damn quick.

 

I had 3.92 and went to 4.56.

City mileage when up around 1.5-2 mpg and highway stays about the same under 65mph, then you lose 1-2 mpg. I have the stock 20's.

 

Same here!!

 

obviously the guy without the 456 gears thinks gas milage goes down ,hes wrong .and if I was him I would'd race anyone with them

 

Are you sure you have 3.73's? As far as I know there are only 3.21, 3.55, 3.92, 4.10, 4.56 and 4.88 available for the Chrysler 9.25 rearend.

 

I have the stock 20" rims with Nitto Terra Grappler 305/50/20 tires. I do my fair share of highway driving and don't want to put the 4.56 gears in if it is not going to be good for the truck. I could always do the 4.10 swap I guess. I'm just not sure where to go from here???

 

The question is, when you are on the highway, how fast do you drive? I have the same size tires and the 4.56's and love them!!!

 

I can vouch for the 4.56's....city driving MPG went up, and highway cruzing is about the same 65~70mph. The big difference is your truck doesn't have to work nearly as hard to get big tires and it's heavy butt moving (I went from 3.73's, which after installing 285X75X17's really sucked)....my rig is a little different (10.5 rear, 9.25 front) so costs may be a little off. I bought the gears and master install kits from Randy's ring and pinion (http://www.ring-pinion.com), was about $800 (Yukon gears)then gear lube another ~$70 (Royal Purple), and labor from a popular local 4X4 shop was 'bout $600 (I did had them install shocks at the same time so that estimate is probably a bit high).....keep in mind these numbers are off the top of my head so don't hold me to 'em

After all is said and done I wouldn't have it any other way, and any other truck I buy will have 'em or I'll move on to the next truck....

 

I would have to say that when on the highway I'll usually do between 75-80 tops.