First off i have a 2004 1500 qc hemi.
I have the 3.92 and the posi-trac, what i was wondering is, if it would be worth it to swap to a 4.10.
I am going to start pulling a 6500lb travel trailer around the Houston area, but I would like to be able to go to the mountians if I want to.
If so how much would it cost?
Where do i get them?
and will i be able to keep the posi-trac, or will i have to buy that set up also.

Any and all help would be appreciated!

 

you're only looking at about a 4-5% increase in gear size ... don't think it'll be that much ... i'm thinking of going from 3.55's to 4.10's which will be about 16-17% jump but i'm looking at the same jump in tire size from 245/70/17 to 285/70/17

i think you'll notice a bigger difference with 4.56's but there's a whole lot of controversy on this forum about that ... let us know how it goes ...


btw ... which truck do you have?

 

i have a 2004 QC SLT hemi

so you are saying that you can change the gearint ratio by chainging the tire size?

also how much would it cost to make the change?

I am some-what mechanically inclined but I have never messed with a rear end!

 

Yes, changine tire size will 'change' the rear gears. Basically, the taller the tires are, the higher (numerically lower) your rear will feel. For example. If a truck with 20" rims and the overall height of the tire is 35" and the truck that has a 3.92 rear, the rear may feel like a 3.23. If you switch to a 26 inch tire, the rear end will feel lower (numerically higher) So if you had a 35" tire the rear will feel like a 3.23, but a 26" tire will feel like 5.14's.

That differnence was greatly exagerated, but you get the general idea.

And rear ends are something that a first-timer shouldn't try. I have never tried one, but have heard that if they aren't set up perfectly then can make some interesting noises.

Chris

 

thanx that helps a bunch.

 

IMO, if your going to keep your stock tire size, then just keep the 3.92's. switching to 4.10 would be not worth your money. I have 3.55 in my 2005 4x4, and I am planning on mounting 35x12.50R17...maybe 18 (not sure yet), but I do plan on going with 4.56 gears. The way I determined this, is by riding in a powerwagon. The powerwagons have 33" tires, and 4.56 gears. The RPM at 70mph is about 2500RPM. And since I'm going with a tire 2" taller, it would make the RPM's even a little lower with 4.56 gears. just my $.02

 

thanx i was think about the 4.56's also but i would still line to know the $ also will i be able to keep my posi track?

 

I think you would be probably be looking at 210 for ring and pinion, 115 for the bearing kit. and if you would like to upgrade the factory Trac-loc(maypop) to a Positive locking diff, Auburn clutch type (no noise) or locker (clicking noise) you can add 350 or more depending on what you want. this does not include install labor estimate.
Good luck, I just bought my gears and locker so thats what i based it on.

 

...yea, just go from 3.92 straight to 4.56's...I felt a huge difference...I'm still in my breakin period so I couldn't tell you about towin yet (I'll be towin my boat later this month)...but I can see where it will only help... from a stop and accelerating to speed it feels like no effort on the engine an tranny.... and goin from 65 to 80 is...uh..wow! I got my gears and install from a local gear shop here in Cali..total was $485.00....I have Genuine gears, they whine a little now and hope as the breakin goes, so wil the whine...will let you know...

 

I can specifically tellyou about towing with 3.92's. I had them in my 05 QC pulling a 27' Cherokee light stand by ... I think I still have the CAT sheets (PS. Traded me QC fer a 06 Mega) ...

OK ... QC 05 HEMI SLT 4X4 SB at the CAT scale. 5740 lbs
With trailer (dry) attached 10340lb.

I took this setup on a trip from NC to Florida ... basically flat no troubles.
I took this setup on a trip to W. VA up I-77 ... some serious grades over long distances. Chugging nicely along between 30-45mph.
I took this setup on a trip to Dollywood (Pigeon Forge) over the Smokies. Less serious grades then I-77 but still not problem.

In my opinion ... dont waste your money. 3.92's are fine. You arent going to be in a rush anyway towing 6500 lbs.

Drop me a line at vidalch_1@yahoo.com and I will send you a spread sheet that works all the numbers out for you.

Coincidentally, according to the books, you may be close to the MANUFACTUER defined limits.