[thacru78]

Can someone explain to me in laimens (spl) terms the difference between the two. Pro's and cons of the two. Both are stock gears. Also why were talking about gears. If a whole differentail were to be submerged in water for a long period of time (days). How would it effect the insides and what would have to be done to assure it is fixed. Thanks. Reason being, I just got a rear end from a flood vehicle that has 3.55 gears. Thanks for the help.

 

[CDP6.7]

Here is some good info previously discussed on Dodgetalk -

http://www.dodgetalk.com/forums/showthread.php?t=9737

http://www.dodgetalk.com/forums/showthread.php?t=44468

 

[sawcut64]

I would definitely pop the cover off the diff to see whats inside, if it's just gear oil your probably fine if it's mixed with water then you'll want to drain it all out and refill it. I really dont see it's a problem either way. I had 3.55's on my Hemi truck and switched to 4.56 and couldn't be happier. I also have 3.55's on my 4.7 work truck and wish I had the 3.92's. Personally with the weight of the trucks and the tall tires I think the standard gear should be a 3.92 with the 4.10 or 4.56 as an option...3.55's shouldn't even be offered.

 

[thacru78]

I tried searching for it but I didn't find any. Guess I didn't search good enough. Thanks Anyone know about the water damage on the differential. THanks

 

[sawcut64]

Talk to a few different drivetrain shops about it, they should be able to advise you better then anyone.

 

[HEMI450HP]

With the 24's you are about to put on, 3.55's are going to make your truck an absolute pig off the line...I wouldnt go with anything less than a 3.92 with the 24's...As for water damage...I am with Sawcut on this one...just have to break it open and make sure there is no water in there...but it will have to be open anyway so that you can swap those gears out.

 

[Rambunkshus]

The 3.55 vs the 3.92? The higher the first number, (remember this is a ratio so the implied second number is 1.00 as in 3.55/1.00) the easier it is for the engine to accelerate the truck so long as the tires and rims are the same diameter for both examples. The reason to go with lower (numerically higher) gears with the 24" rims is due to the larger diameter and the likely greater weight of the tire and rim compared to the stock tire and rim. Sometimes though probably not with the 24"ers, the outside diameter of the tires can be close enough so that gears don't matter as much. Search for a tire calculator on line and you can find out if a rim and tire combination of one diameter can roll the same distance in one rotation as a different combination of tire and rim.

 

[cutting edge]

dont waste your time 355's are a joke i just put 410 in mine and its awsome...

 

[texasdon]

Gear ratios are expressed in the number of rotations your driveshaft makes to get one rotation of your tire. Hence 3.55s will require your driveshaft to turn around just over 3 and a half times whereas 3.92s will require nearly 4 rotations just to make your tires go around once. I just recently switched from 3.55s to 3.92s and with my stock 17's, it made a night and day difference in driveability. Still working on whetheror not it has helped my mpgs but if you are going to a bigger tire, you may want to go to 4.10s or even 4.56s. They'll make your engine work much easier to do the same thing.