Engine/Transmission (1998.5 - 2002) Wanting to change diff gears

[mlockner]

I have a friend with an 02 3500 4X4 6 speed with 4. 10 gears. He would like to get the some taller gears so his rpm is not so high when he is on the highway driving or towing. He called some company and they told him that in order to get to 3. 54's he would have to do an axle housing change. This seemed strange to us. Can someone here please assist in answering what is or is not possible. As much knowledge as this group has I am sure someone knows. Thanks in advance for any assistance.



Mike Lockner

 

[B.G. Smith]

Reider Racing - Gears & Rears We carry high performance ring & Go to this site, they have some phone numbers listed and they can tell you what you need to know. bg

 

[DSeamans]

The 6spd should have a dana 60 up front and 80 in back. Yes you can change the gears. Last summer I did my buddies 98 that had the spicer 70 in back. I'll see if he has the receipt for where we bought the gears. I found them on the net and the were brand name gears and good prices. Its not terribly hard to do yourself. The hardest part was getting the old bearings and races off - I torched them. Match the new shims to the old ones on the carrier and use prussian blue or other pattern lube for shimming the pinion gear. That should have you right on for the backlash. That was my first one and it took me half a day. 40,000 hard miles later and its still working great. Good luck and have fun.



Dave

 

[DHayden]

I have 3. 54's and want to go to 4. 10's. I found it was VERY expensive to swap gears, the best idea was to swap axles with someone with the same setup. Ofcourse finding someone close with the same setup wanting to swap is the hard part. (im still looking)

 

[TWhitfill]

Go to ringpinion. biz Seen them in Diesel Power magazine, nice prices

 

[TBartlett1]

Randys Ring & pinion has good pricing and great service.

 

[FLynes]

I have 3. 54's and want to go to 4. 10's. I found it was VERY expensive to swap gears, the best idea was to swap axles with someone with the same setup. Ofcourse finding someone close with the same setup wanting to swap is the hard part. (im still looking)

DHayden,



If you don't mind going to drum brakes, I'll swap ya. I'm actually looking to go to 3. 54's. You don't live that far away from me. Even if you wanted to keep your disc brakes, I'd still be interested in swapping gears.

 

[Loren]

Mike,



I'd recommend an overdrive transmission instead of swapping gears in two differentials. I had a U. S. Gear overdrive in my 2000 truck and loved it. I hope it will fit in the new 2008 truck (I haven't tried it yet. )



The overdrive is probably about the same price as a gear swap and you get the best of both worlds. You keep the low ratio differential which should keep the towing capacity high, and at the same time you can select an overdrive high gear that is about the same as driving a 3. 25 axle ratio.



The U. S. Gear unit will work in 4WD, unlike the Gear Vendors.



I have never installed differential gears, but I did do my own overdrive installation. It's a complicated job, but if I can do it, it must not be too bad. In my case, I had some vibration after the installation which I attributed to the fact that there was no support under the transfer case that was moved aft about a foot. I fabricated a rubber-isolated support and bolted it to a frame crossmember. That solved my problem.



The overdrive will move the transfer case back about a foot, so you may have to cut the end off the fuel tank and have a piece of plastic welded on. This is not the case for all trucks, but just for some cab/bed combinations. Also, both drive shafts will need to be lengthened/shortened. As I said, it's a complicated installation, but it was sure worth it for me.



You should be aware of this option instead of the gear swap.



Good luck,

Loren

 

[DHayden]

DHayden,



If you don't mind going to drum brakes, I'll swap ya. I'm actually looking to go to 3. 54's. You don't live that far away from me. Even if you wanted to keep your disc brakes, I'd still be interested in swapping gears.

your sig shows you have a 2wd, I have 4wd

 

[FLynes]

Ah, yeah, swapping out the front diff would be a bit difficult, wouldn't it? :-laf

Sorry bout that.

 

[JAlford]

Mike - the vendor is correct about the change of the housing on the Dana 80 axle. I wanted to change my 3. 55's to 4. 10's, and after a good bit of research, I discovered the same.

What Loren has suggested about the overdrive is a good alternative, especially if you do much towing. 3. 55's are great if you aren't loaded, but if you are towing, you are really straining the transmission.

I went with 4. 10's on my '06 just for that reason.

If you have old TDR's - issue 47 page 162 discussed the auxiliary transmission, Loren wrote the article.

Good luck to your friend.

Jeff

 

[mlockner]

Thanks to everyone for their input. I believe he will be going to do the gear vendors things or ? You would think this would be a no brainer, but I guess not.



Regards,

Mike Lockner

 

[Loren]

Thanks to everyone for their input. I believe he will be going to do the gear vendors things or ?

Jeff,

Thanks for remembering.



Mike,

I would urge your friend to consider the U. S. Gear unit first. The GearVendors unit cannot be used in 4WD.



Loren

 

[randrews45]

It is not VERY expensive to change gears

I have a 2002 Ram 2500 4x4 SLT Quadcab Diesel with 4. 10 axles, changing to 3. 54 gears (Dana), also considering 3. 31 gears (aftermarket gears). I can buy both sets of gears plus master bearing install kits for both axles and a bare low ratio Dana 80 carrier for $1000. My mechanic will remove the carriers and pinion gear sets, replace all bearings, ring gear bolts, shims, seals, etc. and transfer the spider gears and clutch packs in my old carrier into the new low ratio Dana 80 carrier, compress in new pinion gear with new bearings and seals, remount new carrier, reconfigure all bearing loads, and gear alignments, in effect a complete differential rebuild with new parts and ring/pinion gears, all labor is another $1000. Total cost with shipping for parts and sales tax, about $2200. With 3. 54 gears, I can get 25MPG in the city and 30+ MPG highway, why I'm changing the gears. With 3. 31 gears, I could get 38MPG highway. Can't pull a 20000lb trailer, but then I only pull a boat or camper.

The Dodge Dealer quoted me $9000 for the same job for both axles. Don't ever use a dealer for that.



The US military is expected to launch an attack against Iran in Sept/Oct time frame. Gas will jump to over $10/gallon, possibly $15 in the same month. You better plan on getting max economy before that event.



The

I have 3. 54's and want to go to 4. 10's. I found it was VERY expensive to swap gears, the best idea was to swap axles with someone with the same setup. Ofcourse finding someone close with the same setup wanting to swap is the hard part. (im still looking)

 

[FLynes]

... The US military is expected to launch an attack against Iran in Sept/Oct time frame. Gas will jump to over $10/gallon, possibly $15 in the same month. You better plan on getting max economy before that event...

I don't know what conspiracy kook or website you got your info from, but that is the last thing the U. S. is thinking about doing.



I think that what you're going to do with your truck is great, though, especially if you do see the MPG numbers you're predicting.

 

[dsherman]

[QUOTE=I can get 25MPG in the city and 30+ MPG highway, why I'm changing the gears. With 3. 31 gears, I could get 38MPG highway.





Is this going only down hill:-laf:-laf

I have a 2002 Ram 2500 4x4 SLT Quadcab Diesel with 3. 54 axles, (Dana).

And all I see is 20 to 23 MPG on highway @ 55 miles an hour.

And towing 15000 LBS I see 12 to 16 MPG @ 55 on highway.

Keep us posted

 

[randrews45]

Better Diesel Fuel Economy

You must have other issues that combined are robbing you of fuel economy. I use the K&N air system and filter, ripped out the big filter box which creates a vacuum, greatly restricts air flow to the turbo. That and a dirty filter will rob you of great fuel economy. Using 35" size tires also helps improve the wheel ratio. Keeping tire pressures high reduces rolling resistance, which also helps. Driving with the tailgate down (acts as an air brake release) greatly reduces air drag, also helps most at highway speeds. Todays low sulfur fuels are not meant to be used in our engines, lacks sulfur which lubricates our rings. Adding diesel fuel additives lowers friction in the rings and bearings, which reduces engine friction, thus improves fuel economy and engine life.



Turning 1400 RPMs instead of 2000 RPMs while driving 60MPH which is a result of using lower gears should cause a big increase in fuel economy. I'm getting 17MPG highway with 4. 10 gears on 35" tires.​

 

[SAndreasen]

i would like to put a overdirive unit in my 01 it 3. 54 gears and i can go 80 at 2000 rmp but i would like to drop that down how are the us gear units made i mean is it a clutch pack like the gv unit ? the gv dosent look like it would be heavy enough for me since im usualy loaded to about thirty thousand gvw.

 

[randrews45]

3.31 gears

Yukon makes a 3. 31 Ring and Pinion gear for the Dana 80 and its is available, but they do not make it for my Dana 60 front diff and no other manufacturer makes it either so I'll have to use the 3. 54 gears.

I have a 2002 Ram 2500 4x4 SLT Quadcab Diesel with 4. 10 axles, changing to 3. 54 gears (Dana), also considering 3. 31 gears (aftermarket gears). I can buy both sets of gears plus master bearing install kits for both axles and a bare low ratio Dana 80 carrier for $1000. My mechanic will remove the carriers and pinion gear sets, replace all bearings, ring gear bolts, shims, seals, etc. and transfer the spider gears and clutch packs in my old carrier into the new low ratio Dana 80 carrier, compress in new pinion gear with new bearings and seals, remount new carrier, reconfigure all bearing loads, and gear alignments, in effect a complete differential rebuild with new parts and ring/pinion gears, all labor is another $1000. Total cost with shipping for parts and sales tax, about $2200. With 3. 54 gears, I can get 25MPG in the city and 30+ MPG highway, why I'm changing the gears. With 3. 31 gears, I could get 38MPG highway. Can't pull a 20000lb trailer, but then I only pull a boat or camper.

The Dodge Dealer quoted me $9000 for the same job for both axles. Don't ever use a dealer for that.



The US military is expected to launch an attack against Iran in Sept/Oct time frame. Gas will jump to over $10/gallon, possibly $15 in the same month. You better plan on getting max economy before that event.



The

 

[DHayden]

I try not to be a pessimist, but I would love to see factual, calculated information from anyone who gets 30 miles per gallon in any of our trucks. Allot of people have done testing on this board and many other places with some smart cookies and the tailgate being down actually makes mileage worse, the best intake whether gutted or the best filter with removing the box is minimal gain especially compared to what you are talking about.

Gear ratio will help to an extent but again not anywhere close to what you are hoping for. The gains are not linear on any of these solutions nor with a overdrive unit. Good luck to you but you can find alot of information with people who have tried all of this before looking for the "holy grail" and just ended up spending alot of money. If you do it and it works with provable results I'll be the first one to eat crow, just hope you dont spend alot of money on a pipe dream.