Alright fellas. I checked with a shop today and they told me around $650 to change to 3.92. He then said i would have to get with dodge to reprogram my computer. He thought that would cost around $100. Im pretty sure this will ruin my warranty though. Also, i talked to my dealer and a service tech told me the mds only kicks in around 60 or 70 on the highway and you cant feel it. He said it doesnt kick in at 30, 40, or 50 mph. But he did say my computer might need tuned up. I just want some of you guys opinion if i should mess with the gear change. And is it that big of differance. Thanks

 

The service tech is an idiot. MDS can kick in at any speed when the load on the engine is low enough.

Changing the gears would void the warranty on the gears/carrier/bearings but that should be about it.

 

Seems like WAY too much $$$ and hassle for a tire that's only 2" bigger than stock. Then again it's not my money.

 

X2

My MDS kicks in at 25 constantly. And 35, and 45, and 55. Rarely over 60 does it come on.

 

x2 on the service person being an idiot. MDS comes on at all speeds. I've had mine kick into MDS just while tooling around the neighborhood at 20 MPH.

As for the computer change, another line of BS. I've changed my gears, going from a 3.55 to a 4.10 and there was no computer change involved.

As for the warranty, yes, you'll void it on the axle. Anything goes in the axle and Dodge will pin it on the gears and you won't have a leg to stand on. Outside of that though, the rest of the warranty will remain in effect.

 

Is when the eco light comes on the front screen does that mean the mds kicked in. If so the service tech is a dumbass.

Meanwhile on the gear change, im not goin to mess with it if its minimal change. But if its from going to change my zip like going from a focus to a mustang then i think $700 is worth it. If not $700 is a big waste of time and money.

 

Took this just a few minutes ago coming home. As you can see, about 7MPH and MDS's Fuel Saver light is on. It'll stay on until you either come to a stop or give it a little too much gas.

It should be noted though, I don't think it's exactly this way on all trucks. If you've got a 2009 that hasn't had the MDS RRT (came out about 4 or 5 months ago), then your MDS will act differently.

 

Not only the 700 bucks, but it is not worth the worse highway gas mileage. If you do alot of towing to justify it...then maybe.

 

My 2010 has never had fuel saver come on the screen. All i have seen is at the top it will say ECO. The damn manual doesnt say what it means. But i recently drove from wichita to kansas city going 75 and got 19.8 mpg. My 06 f-150 was getting 13 mpg. Ford sucks

 

I can't comment on all this programming and MDS stuff, I'll claim ignorance.

But if what your looking for is a quick kick in the seat performance mod, you can't go wrong with changing out those gears.
I remember when I was a pup, swapping out the 3;21s in my old Roadrunner for a set of 3:91s. yeah, old school, but the benefit is the same.
The first time I took it for a drive, I wondered if some gnomes had also magicly replaced a very healthy 340 with a big block. Sure I lost some top end...about 20 mph. But 115 will kill ya as fast as 135. Back then we didn't have MDS, lockup TCs, or even overdrive. Just 3 speeds a 3500 stall converter and a slapstick.
But I degress...(wipes tear from eye)
I also shaved 9/10ths off my et with no other changes. Zip, Nada, 2nd gear smokeouts, no problem. Mileage, it already sucked...go buy a Prius...or back then, a Chevette. And remember, no lockup TCs no OD, no MDS.

It's your cash bro, but if you're looking for a BIG bang for the bucks, you found it. Your detractors will only gnash thier teeth as your tailights disappear through the haze of your tires fighting for traction. Have fun!