Engine/Transmission (1998.5 - 2002) What to change gears in rear end

[RCrosby]

Question I got is about changing gears. I have an 2001/2500 auto with 410 gears, I no longer pull our camper. It is parked at our property in miss. I am looking at going with 373/353 gears if possible. I average about 18/19 mpg now. At 65 mph tach is showing 2000 rpm's it should drop some rpm and help for the fuel milage. Is this a good thing to do, the truck has only 120,000 on it. What else will i have to do. I work 7&7 the truck is not used when at work, got a company truck. Use it only to go to the camp in miss. Thanks for any info.

 

[JR]

I have the 3. 55s and I feel at times they are too tall. For just driving down the freeway like I think your referring too, they do ok, but will only do marginally better than what your getting now. ( I will just break 20mpg empty on the freeway). All other times, I wish I had the 4. 10. The 3. 55 are ok for towing light, but getting up towards the 10k mark or hauling on grades I quickly fall out of the sweet spot and have to drop down to 3rd gear (auto trans). There is the option of doing the 3. 73 split, but unless you can find somebody to straight swap you gears, its going to be quite pricey and for the extra 1 or maybe 2 mpg it will take a long time to recoup the costs. Im sure others will have different opinions, Ive had both 4. 10 and 3. 55 and I prefer the 4. 10.



P. S. if we were closer, I would swap you gears in a heartbeat

 

[fox]

You could consider taller tires. Like 235-85/16
If you find someone to trade, it might be wise to swap complete axles.

 

[fox]

You could consider taller tires. Like 235-85/16

If you find someone to trade, it might be wise to swap complete axles.

 

[HBarlow]

The cost of the gear swap will far exceed any fuel savings you might see. Load, terrain, and wind have more effect on fuel mileage than the difference between 4. 10 gears and the optional 3. 54 gear set for your Dana rear end.

With a 47RE a 4. 10 gearset is a good choice. My advice would be leave it as is.

 

[drag racer]

You could consider taller tires. Like 235-85/16

Precisely what I did on mine, and it results in something resembling 3. 73's, and did exactly what I wanted it to. My real-world, hand calculated mileage has been as high as 18. 8 (mix of loaded 10k/unloaded, AC on, etc. ) and went up 1-2 since doing the tire upsize.

 

[jmos4]

Hi,

Ive got 3. 55's in my 99 4x4 now and am thinking about finding a 4. 10 set as I am running 315-75r16 and the 4. 10's woudl get it back to where the 3. 55's are stock so maybe consider taller tires as it would be cheaper than the gears and carrier/posi

good luck with the decision
Regards,

 

[JLeake]

I looked at drivetrainspecialists and one set of ring and pinion for a Dana 80 is $500 - and plus bearings etc and you would need two sets, so $1000 before you get ready to change them out. Dana's and the American Axle equivalent require a spreader to get the ring and pinion out, not something most people have in their garage. Bigger tires are MUCH cheaper and easy to change. Unless you know someone who has the tools and parts or swap the axles.

The Ford 9" and the old Mopar 8 3/4's are much easier to change (swap the third member) been there done both.

 

[LNaugle]

levling kit and 34s or 35s will change your gearing enough and is less expensive... . I swapped out the 3. 55s for 4. 10s in my 96, wish i would have done 3. 73s, thought i was going to be running 37" tires though...

 

[Cosmo]

Dana's and the American Axle equivalent require a spreader to get the ring and pinion out, not something most people have in their garage.

We did a D60 front without a spreader a month or so ago. It makes it a little easier, but even when I was working for the auto group the dodge franchise didn't use a spreader...

 

[VolsFan]

I agree with diesel4life on 3. 55 being too tall at times. My auto 99 had 4. 10 gears and I loved that setup for an auto anyways, it would pull grades like nobodys business. My dads auto 99 which he still has has 3. 55 and it wants to downshift seems like at any mention of a grade. And I got better fuel mileage, didnt make sense to me. 18/19 mpg is pretty good. As everyone else has mentioned, put some taller tires on it. I almost went to 255/85/16's back in early fall of '10 but tires store persuaded me to stick w/ 285's to 'fill the wheel well up'. Rcrosby, I dont think you'll be happy swapping 4. 10's for 3. 55. esp. with the cost of doing it

 

[JLeake]

Seems to me that a change to taller tires will be the cheapest. Given you only use the truck occasionally the overall cost to change differential ratios, etc getting taller tires when new ones are required (or a second set) will be the most cost effective solution. I've lived in Southern Mississippi years ago (Waynesboro), and it is mostly flat so the taller tires should not be a big problem if you end up towing some.