This has probably been answered a few times before but, I want to swap my gears out from the 3.92s (stock) to either a 4.11 or 4.56. My questions for those of you that have done thisis:

A:By swapping out the gears does it "fix" the C-clip problems that our rear ends have?

B: Likes or Dislikes after adding them?

C: AnyNoticeable improvements in acceleration or mpg?

 

A - NO, its still the same rear pumpkin.

B - I put in 456 and love it

C - YES in both. mpg went up around 1.5mpg and you can feel the difference in acceleration.

 

Wait, you put in a higher gear ratio and got better gas mileage? I thought higher gear ratios lowers fuel economy?

 

So really the only way to "fix" the c-clip problem is to replace the entire rear end? Oh well, is there anything that can be done to the c-clips while the new gears are being installed to make them a little less likely to break? From all the posts on here it seems like right around 30k-40k is about when they decide to fail and my truck is right around 38k now....

 

My truck weights around 5800+ lbs and sits on stock 20" wheels, 33" diameter tires.

It takes a lot of force to get that schoolbus rolling. I had 3.92 gears and went to 4.56 gears.

The engine works a lot less now because the gears give it a mechanical advantage. It's also easier on the trans.

So, yup, I get better mileage as do all guys that went to 4.56 gears that have 33" tires.

I just stay at/under 70mph.

 

The "C-Clip" issue really has nothing to do with the rear end, per say, it's strictly an issue with the stock Limited Slip Differential. If you do not have the Chrysler LSD, you'll never have the issue! You can have it removed or better still, replaced with a far superior aftermarket unit such as a Eaton/Detroit TruTrac or Auburn Gear LSD.
As far as the gears go, yes, you'll actually see better fuel economy in all situations except high speed sustained driving like trips on the interstate at above say 70-75 mph. Performance will improve dramatically. Although I'd not mess with the 4.10s, not enough difference from your stock 3.92s to justify the cost, IMO. I'd go straight to the 4.56s. I have them with 35" tires and the difference from my stock 3.92s is night and day...

 

Notice that for model year 2009
Dodge is offering the 3.21 diff gear as an option for all Ram engines & models?

Notice when ex-Chrysler vice chairman Bob Lutz redesigned the GM pickups
he dropped the diff gear from the old standard GM 3.73 to to a new design 3.45 ?

Note that Nissan uses 3.3 diff gears on the Titan?

Note that when Toyota put 4.10 and 4.30 diff gears on the Tundra
they compensated for that
with a 0.59 overdrive top gear in the transmission?
{always use MPH per 1000 rpm to judge the drivetrain rather than diff gear}

If you are not a WAG'er
these things ought to clue you in to the fact
that no automotive engineer will tell you that your MPG will go up
with a numerically higher diff gear
and they know this because they have tested several pickups
in 'convoy style' where the trucks all travel the same roads and speeds
over many thousands of miles in varied conditions.

 

That sounds good, but the FACT IS my mileage and everybody else that went to 4.56 gears went UP.

 

Ignore Hank, I've had him blocked for months. The poor soul hasn't got a clue and obviously just repeatedly posts counter opinions so he'll have something to do.
I've got an old college buddy who's actually an engineer with a major diesel engine manufacturer. When asked about why passenger trucks have such lousy gearing, he said the major reason is to meet governmet emissions standards. The lower the rpm's at a given speed, the lower the emissions. It's accepting lower performance to meet the tougher standards, kinda like when gas went from leaded to unleaded...

 

THE ONLY QUESTION I HAVE IS DID THE MILEAGE ALSO GO UP ON THE 5.9 360? I have the 5.9 gas engine and all the posts i see the the HEMI'S gas mileage went up havent seen anything on the 5.9. That is the reason i left my 3.92's in when i put the auburn in didnt know what it would do to my gas mileage.