2nd Gen Non-Engine/Transmission Gear Swap

[Bunyan]

I have an 01 2500 5spd with 3. 55 gears. I want to change to a lower gear. My question is what do you guys think. I tow 5-10000lbs most of the time. I run 285/75/16 tires. I was thinking 373, 390, or 410s. Are any of you running something close to this set-up? What about you guys with 410s and larger tires?



Thanks,

Bunyan

 

[HBarlow]

The two gear choices offered on Gen II trucks were 3. 54 or 4. 10. I would suggest the 4. 10 gears for towing. The old NV-4500 had a tall overdrive ratio and the 4. 10 gear would be acceptable when running empty and a huge improvement when towing.

 

[surfbeetle]

My 95 had 4. 10 gears when I first bought it. Top speed empty was just over 83 mph, yes it towed great but when you are empty and traffic is really moving, it was no fun. I switched to 3. 54s and the top speed is 95. I have the nv4500. My current fifth wheel is 11,000 lbs and I have no issues towing even with the higher gears. I am running a 4 inch exhaust and a #5 fuel plate. My tires are 285/75R17 on the 2005 wheels.

 

[GAmes]

Going to a smaller diameter tire would be a lot easier, and maybe cost less. Stock tire size on my '97 is 215/85R16, and I've had no trouble towing heavy (meaning lots heavier than 10,000). You might consider 235s.

 

[Mhannink]

I don't think tire size is a problem, 285 is very close to stock. Personally I would stick to 3. 55s infact that's what im switching to in athe few weeks I think it is actually better for the truck and trans. If you want lower gears I think 3. 73s would be ideal. I tow heavy but not often but I tow heavy > 10k lbs. 4. 10s are too low even for me even on 6% grades.

The 3. 73 has two advantages. First they are lower and will get your rpm down closer to if not on your target rpm. Second thing is cost, 3. 73 is the gear split on the dana 80. It will work both on 4. 10 and 3. 54 carriers. You just need to get the thicker or thinner ring and pinion set. That makes it a he'll of alot easier to find, and if your buying all the parts new its also cheaper.

 

[KBurgoyne]

check out west coast differentials website. they have an rpm calculator for tire size, gear ratio, trans and speed.

Differential Gear Calculators | West Coast Differentials

 

[Bunyan]

These trucks originally came with 245/75/16 (31 inch) tires. With the intoduction of the alloy wheel came 265/75/16 (32 inch) tires, the gears stayed the same and the ratio drops. I like the look of the truck with my current tires 285/75/16.

 

[Bunyan]

Put in the 3. 73 gears and what a difference. Should have spent the money years ago. I have five hundred miles on them and took the 16ft trailer for a pull yesterday and did very well. No more lag between gear changes. At 70mph the truck rpms are 2000, 75 @ 2200. Unloaded this thing will get up and go. The tailer had about 500#s on it for a total weight of 3200#s and you could feel the torque pulling. When i get more mileson the gears I'll update on towing with heavier loads at various speeds. Bunyan

 

[Bunyan]

Well gents, best money ever spent! 5000 miles on this new gear set up and in city 2. 5 mpg increase. Lag at gear changes is gone!!! Running on cruise the engine would slow driving down hill with the HEAVY THROTTLE RESPONSE going up the next hill. This is not so no anymore. Highway driving is 20. 4mpg. City mpg with 3. 55 was 14. 6, hwy 17. 4. My 99 was getting the current mileage after six months. I want to take this time to thank everyone here for the help through years. I was diagnosed with pancreatic cancer in July 2012. So my time is limited. Best wishes to all. Thanks again, Bunyan

 

[JMcCoy]

I am glad to hear your gear selection is working out so well. I'm truly sorry to hear about your diagnosis. Miracles happen every day. You will be in my prayers.

 

[Bunyan]

I am glad to hear your gear selection is working out so well. I'm truly sorry to hear about your diagnosis. Miracles happen every day. You will be in my prayers.

Thank you, JMcCoy. Yes they do!!! I'm being optimistic. I've had so many blessings and prayers answered over the past several years, I can't help, not to be.