Ok folks so I got a 2001 3500 4x4 with a six speed, and at 100km/60 mph I am turning 2100 rpm's with 235 tires. I believe the ratio is 4.10

What is my best option to get my revs down, at 70 I am spinning almost 2400 rpm and I can't see this doing wonders for my gas mileage.

Gears front and back or bigger tires front and back, I am in need of new tires anyways but 6 tires plus wheels might get more expensive than a new set of gears.

 

Yes, you have 4.10's.....you can swap in 3.54's for a lower cruising rpm but it won't be cheap. Going ip to 285's will help lower the rpm but will not be quite as much of a change as going to 3.54's and you will also require some wheel spacers for the rears....you could go to even larger tires but at that point, you will require some additional lift over stock to clear them (read more money!) Either way, it will be expensive but buying gears for the front and rear and having them professionally changed would likely be cheaper than 6 new large tires, spacers and mounting and balancing.

 

I know from experiance that gearing is expensive. I used to have 4.10's. I got all of my stuff used. My best price was $720 for a LSD carrier and 375 for 3.54 gears. You can get 3.31 which is what I wanted but they were $680. They are a DANA only thing. I have found some 235/85/R16 tire that I will put on mine when I change tires. That will give me 31.7D I belive and get my 70 MPH right at/under 2000 RPM.

CTD NUT can give you a better idea on the front end price. And the 3.54 stuff in not easy to find used. It took me around 6 months.

Randy

 

Check you local junk yard. at least by me they have a network they can tap into for parts.

 

Hey I just happen to have a 01 with 3.54's and was wanting some 4.10's HMMM....

Does your truck have a LSD? Also is it a SRW Dana 70?

Dan

 

2nd gen 3500's were only available as DRW's and were all equipped with a D80 rear.

 

Would 3.54's be my best choice or would 3.7's be a better choice, I do haul a bobcat through the mountains and don't really want to go that far for gearing.


Thanks for the info, I will look at some local yards and make some phone calls, I want to also do the math on tires, got a local used tire shop that carries bigger wheels, maybe he has some 8" that I can get of him cheap.

I know dreaming.

thanks

 

I run 235/85R16 tires with 3.54 gears and turn 2000 rpm at 70 mph. I find this to be perfect!!! If you want a 3.7 ratio, just put taller tires on! I wouldn't change gears for that small differance.

 

I just swapped gears and went the other way because of the 35" tires and mostly towing. I bought my gears off ebay. Lets just say it costs you 450 bucks for ring and pinions on both axles and carriers for both. Then I think book time for install is 12 hours. 12x 70labor rate, is 840 plus the 450 is about 1300. That is if you dont have to get bearings or seals, but there is a chance you probably will. Plus it is a good idea. Add another 250 bucks for bearings, seals, and fluids on both axles and that is a low estimate and you are at 1500 +/-. Now I wanted lockers in mine so I did the gear swap. If you dont care, put in an overdrive type unit from gear vendors or something like that. It will actually double your gearing, still have the 4.10's for pulling, and a low ratio for when you are empty. They cost about 2000 +/-. I would consider that. Best of both worlds.