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what diffs do I have

2K views 21 replies 5 participants last post by  sweet03cobra 
#1 ·
I went on the amsoil website so I can order the fluid and whatnot for my diffs, tranny and transfer case and after I put in my info, it gave me about 100 different combos. I have a 2008 Dodge 3500 6.7 TD 4x4 Megacab auto. What rear end and front end diffs do I have. I'm pretty sure my tranny is a 68rfe but when I started looking for the tranny filter and all that jazz same thing. Does anyone know forsure exactly what I need for filters and oil? Thanks
 
#2 ·
Front = AAM 9.25"
Rear = AAM 11.5"
 
#4 ·
anti = anti-spin (limited-slip differential)
open = open diff (only 1 tire spins)

Do you know if you have factory limited-slip or not?
 
#6 ·
I can't ever remembering spinning and only 1 tire spun, i'm pretty sure the rears always spin together. when I'm in 4 wheel and turning she jumps and jerks pretty hard so I'm assuming my front isn't open either then
 
#7 ·
You probably have front and rear limited slip diffs. Call Chrysler or your local dealership and give them your VIN number and ask them if it says it has LSD's or open diffs. They can tell you.

Or, if you bought your truck brand new you can look on the window sticker that lists the options.
 
#9 ·
There's no LSD option for the front. The bucking and chucking in 4wd is because the front and rear driveshafts are locked together and must spin at the same speed. Has nothing to do with the diffs.
 
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#10 ·
There's no LSD option for the front. The bucking and chucking in 4wd is because the front and rear driveshafts are locked together and must spin at the same speed. Has nothing to do with the diffs.
Well, my truck sure isn't open diff in the front.......If it's not open, then what is it? And no, I haven't swapped anything in it.
 
#12 ·
No, both front tires spin evenly under stress.
 
#13 ·
All that tells you is that:

a) You're applying enough torque to overcome the friction of both tires
b) You're not getting much traction

With equal traction from both tires you'll spin both at the same time with an open diff, an open diff sends equal torque to both sides. If you're getting on the throttle good (Looks like you like mud) then it's not very hard to overcome the traction of both tires even with an open diff.

There's a really easy way to determine if you have an open diff up front and it doesn't involve opening it up. Just jack both front tires off the ground and spin one of the tires. If the tire on the opposite side rotates the opposite direction then you have an open diff. If it rotates the same direction then you have a limited slip.

But, if you bought the truck new or it was stock when you bought it then you have an open front diff, no question about it. The only Ram that has any traction aid in the front from the factory is the Power Wagon, there was simply no option for it on standard Ram trucks. The only option is for the rear.
 
#16 ·
Definitely an open diff. Yahoolagin mentioned it already, "The only Ram that has any traction aid in the front from the factory is the Power Wagon, there was simply no option for it on standard Ram trucks. The only option is for the rear."
If it were a used truck, there would be the possibility that the previous owner added something. Try this: Find a trench of some kind off the side of a dirt road or offroad...in a safe place. Should be about 2-3' deep and only about 6' wide. Staddle the trench diagonally and blurp the gas "Go and stop" at a slow speed and look to see if the dropped out tire spins and tills up some soil. You just need to break the tires loose, nothing more to see this. Or ou could just try some more Legal offroad activities that are more technical. After a couple trip you would know for sure. Plus side to that is you get to go wheeling for science...or something:thumbsup: If it doesn't grab or show signs of being "Driven", its open.
 
#18 ·
What I found out when I bought my 2010 crew cab 2500 is that the factory LSD rear axle was an option on the 2500, but was STANDARD on the 3500.

I doubt the running gear changed between 2008 and 2010. Since you mentioned that you have a mega cab dually, that tells me you have 3500, so chances are pretty good you have a factory LSD in your 11.5" AAM rear axle.

(I wish I would have insisted on that option for my 2500, my rear axle keeps breaking free on the wet washington roads.)
 
#20 ·
Well my wife sent me a picture of the window sticker...I do have the "anti-spin differential rear axle" which was a $325 option. I also have the 68RFE tranny. It also says I have the 9.25 front axle with the hub extensions...so it really doesn't say anything else about that. So there ya have it, now I just got to find the best fluids and filters, the best deal on those things, and place my order. Any ideas?
 
#21 ·
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