I have a 2wd 4th gen hemi with 3:55. I am ready to go with the 4:10 or 4:56. No one in 4th gen has exp with 4:56. but a lot of you guys do. In my 2009, i swapped my 3:21's for 4:10 and although it was nice, it still wasnt a holy sh*t difference. I never had had the computer flashed when i changed gears- dont know if that would of made a difference or not. I have a 2010 now with cooper zeon 275-60-20's. I am interested in the 4:56's. I will buy the superchip programmer at the same time to make the needed adjustments. any input on you guys with gears on standard tires would be of great help. truck going in shop next week!

 

You don't need to make any adjustments for gearing, just tire diameter.

I went from 3.92s (stock) to 4.56s not long after I installed my lift and went to 35" tires. Night and day difference for me, but IMO 35s need 4.56s...

 

What all is involved in changing gears (both cases)? I read where you stated that one should find a mechanic well-versed with our trucks, particularly. What should I be looking for in a mechanic to do this? What would make me want to immediately turn around and look elsewhere?

As you can guess, there probably aren't a whole lot of places in my neighborhood that fit the first statement criteria. However, I'm sure if I posted something on the Yardsales (Craigslist'esque) site asking for help, I'd get a ton of hits from people with experience ranging from "I can change my own oil", to ASE certified mechanics. Basically, how should I know if someone knows what they are doing or not? Gears are something I am looking into doing for the truck, and from what I've read it's not really a novice DIY job...

 

Double post... oops.

 

Hammer- You said you have 35's. Would 4:56 and 33's be a potential problem? 4wheel parts quoted me at 1500 out the door for the gears, install, and detroit lsd or locker. This seems a little steep. think they will come down. Please give me your thoughts on these 33's ( 20 in rims ) and the gears. I like trucks that grip hard. is this gearing to much. Talk to me- i value your opinion. and others as well.....

 

No, because the 545rfe has essentially two overdrive gears, 4.56s with 33s is fine. RPM's will actually just be right about in the middle of the Hemi's powerband at highway cruising speeds. With just a four speed for example, you'd be above that band where power takes the forefront over fuel economy.

I wouldn't do a rear locker in a daily driver, in a 2WD, or even really in an IFS 4x4 for that matter - unless of course it's selectable (you can turn it off) and I don't think anyone makes a selectable locker for an AAM 9.25" rear. Pick you a solid LSD with a fairly high bias and you'll get about all the traction possible without the ratcheting effect while turning. I don't care who says lockers are invisible on the road, the difference in turning speeds on turns between wheels is gonna engage it and you don't want it to engage on pavement. Besides the annoying ratcheting effect, you'll wear out tires and hubs a lot sooner.

Good mid-high bias LSDs are the Detroit Tru-Trac and the Auburn Gear LSD. The Tru-Trac uses a worm-type gear and in theory should never wear out (although even Detroit doesn't like to see it used on tires over 33" - but 33's are fine), the Auburn uses conventional clutches and require a friction modifier and yes, the clutch packs will wear over time (rated life is 100k miles) and at some point after that would require a rebuild or replacement.

$1500 is a bit high for a single axle, but 4 Wheel Parts as a rule has experienced gear installers and is a national chain, so expect to pay a premium. My local 4x4 shop charges $600 per axle for gears, install kit and labor and add about $550 for a Tru Trac and $500 for an Auburn unit which is about the best price you're gonna find.


Chet:
The AAM axle is a known b*tch to set a ring and pinion in. It requires very precise shimming. 99.9% of guys who have never shimmed an AAM axle don't get it right the first time - which could result in ruining your new ring & pinion or even differential damage. Find you not only someone who does gear/axle work on a routine basis but also who has experience installing them in Ram trucks...

 

That's what I needed to know. Thanks!

 

Ok. Going to go with the 4.56. Hammer- so my computer does not need to be flashed? Are shift points and all that not that big of a deal? I also don't want to fudge up the computer. I don't know shiat about this- just asking. Rpm's won't bother the computer? Any thoughts on gears to buy? Spicer? Thanks Hammer

 

Cross cannan I have 04 5.7 I run 285/70/17 almost a 33. last year i went from 3.55 to 4.56. Mainley for towing. Wow what a differance. I get 17.5 unloaded and 12 towing. (7800 LB) RV. Its worth every penny. It puts the HEMI right in the sweet spot like Hammer said.

 

Thank u p38252! I'm dead set on 4.56 now and can't freakn wait.
My only concern now is the computer and how it will take the gear swap. Any thoughts? Thank u Hammer and P38252. I really appreciate the solid advice.