Ok, I know the gear swap is a hot topic so I thought I would post up on mine. This will probably be ongoing for a couple of weeks. I'm going to have my wife drive the truck into Dallas for a week or two to check fuel mileage. Anyway $314 in labor later, I was expecting more than I got at first. I was figuring I would tough the gas and it would launch off the line pulling out of the parking lot. Not so much. There was a definate difference though. You do not have to give it as much gas to accelerate. The transmission also shifts quicker like it's hitting it's shift points faster. I guess that would make sense since the gears are lower. Not really being able to open it up in town, I took it out on I-20 to see how it did at highway speeds. At 70 mph I'm at 2500 RPM's on the dot about 300 more than what I ran before. I have the 17" stock tires. I immediately noticed once the truck leveled out at it's cruising speed, my exhaust was quieter. I'm assuming this is because the higher ratio reduced the work load of the engine. I'm practically running a straight pipe having installed a 12", 2.5 ID glasspack - not the Autozone cheapo but a nice stainless setup. The reduced drone at 70 mph was very pleasant and when going up a hill, the truck does not slow down like it used to. It just chugs away. I got it up to about 85 and felt a vibration, almost like running over the graded marks on the shoulder of the Interstate that is supposed to wake you up. Not the sound but a vibration that was similar. This did not happen at highway speeds just at 85 mph and up which, btw the truck gets there much quicker now. I'm going to talk to my mechanic about it tomorrow. So I turn around and find a little FM road to cut through to the house. OK, here is where I get impressed. This was your standard road not blacktop. I have never been able to make this truck spin the tires on dry pavement. I stopped, powerjacked up to about 2000 rpm's then let off the brake and hammered down - TWO black marks about 20' long and I DO NOT have limited slip. The truck even got sideways a little. Here is where I can tell the power is getting to the pavement! I'm not sure where it shifted from first to second (stopped spinning once it hit second) but second to third was at 5400 rpm's.
More to come...............

 

Nice little story and i see you have the 4.7L not the 5.7L Hemi. I know the guys with the hemi and the 4.56gears really light up the tires.

 

WELCOME to the 4.56 CLUB... I see you live in the DFW area... I wish I new that... my gear guy does gears for 425.00 parts labor out the door... thats EVERYTHING... but it looks like you got a decent deal as well ... The 4.7L really loves those gears... I have the same exact shake... I feel its the driveshaft ... think about it... the RPMs of the driveshaft have increased... so at 80MPH it is spinning much faster than it did before... I have not had the time to take mine in to have re balanced.... but im betting thats the fix. I do know that if you PUSH through the shake it goes away at approximately 90MPH...

SPEED SAFE, AIR RAM

 

Hey Airram... if you could give me a line on your gear guy i would appreciate it... i am looking for front and rear gears and i live in BFE texas so driving to dallas is probably the way to go... If you could get me a quote on front and rear i would appreciate it.

 

Hey Nick. Doing the gear swap proved a statement you made not too long ago and I thought your were crazy then. You said when you accelerate, stay at 2000 rpms. I tried it in my old setup just to see if you were on the mark. There was NO WAY I could do that with the 3:92's without getting run over. With the 4:56's it's very much possible. I shift out at about 2200-2300 rpms and it still accelerates nicely with traffic. My wife is lighter on the gas than I. I'm sure she will be able to do the 2000 rpm thing.

 

His name is Jason, he owns Texas Drivetrain Performance.... His phone number is 817 300 6840 ... Dont forget to tell him AIR RAM sent you... He will take care of you...

SPEED SAFE, AIR RAM

 

Yeahh I remember back than when EVERYONE was telling me I was crazy ... I’m glad you where able to sift through the BS and make an informed choice as to what gear would improve all round performance in your truck. And what you have reported back just backs up why you should be take the advice from those who lack first hand experience with a grain of salt. There are a few people who don’t even own 3rd Gen Rams and the advice they offer is misleading at best. Now you have first hand experience and you get to argue with the naysayer with me... LOL ... Welcome to the 4.56 club.

PS: The NAYSAYERS will all say its NOT possible to see the improvements that you say you are with 4.56 gears... and if you say your seeing better fuel economy then according to them your a liar and can not be trusted. And your personal "FIRST HAND" experiences do not count any more than there personal "UN-experienced" opinions unless you have a 3rd party from a 4th party do the testing to back you up but they will tell you that the test must be done in 3 different countries with 16 different drivers in sealed laboratories with no doors or windows and anything showing positive gains must be tossed out as they are non conclusive But all negative results will be posted as FACT because that’s what grandpa used to tell them when they where little whippersnappers and that is how it will be because it has always been that way. No positive gains will be accepted. (Did I get that right hank?)

SPEED SAFE, AIR RAM

 

to bad when you do get the tires spinning with 20's and LSD the whole *** end of the truck bounces off the ground and knocks your teeth out.....even on dirt my truck does this. feels like the back tires are coming 6 inches off the ground...im waiting to hear my rear end gears rolling down the road.

 

Are you guys seeing any improvement in gas milage with the 4.56 gears? And did you all (4x4 guys) replace front and rear gears? I would assume that you had to do both sets or it would affect the 4wd.

 

Others swear fuel mileage gains. I can't say yet. I should be able to post something by the end of next week though. My wife drives around 400+ miles a week and I figure 2 weeks of driving the truck will tell if the mileage goes up.
Good thing about it is her gas is paid for by the company!........
And yes, you will have to replace front and rear gears



or you can use different size tires for the front with a specific gear vs. different size tires with the rear with a spacific gear....
( I had to post that. Some knucklehead will chime in with "Nuh uuhh, my pappy used to..........blah, blah, blah........and he got 48 miles to the gallon driving backwards everywhere he went!")