Gear Set Between 3.73 and 4.10?

[trqmnstr]

My current 3. 73's are too high and I believe 4. 10's will be too low. Are there AAM 11. 5 gears in between those two sets? 3. 92?

 

[WestTN]

You are only looking at a roughly a 5% difference between 3. 92's and 4. 10's or 3. 73's. It is hard to see that gearing would need to be that closely chosen for any load. The spread from 3. 73 to 4. 10 is only 10%.

 

[trqmnstr]

3. 73 puts me too fast for my trailer. 4. 10 is too slow. I just need something in the middle. I like to be at 2k rpms on the highway. Not looking for opinons... just want to know what's available. Thanks

 

[tkerrigan]

What RPM's do you get in third gear, if you don't use overdrive? If a little to buzzy, just get taller tires next time. Third gear is the most efficient to use friction wise.

 

[trqmnstr]

What RPM's do you get in third gear, if you don't use overdrive? If a little to buzzy, just get taller tires next time. Third gear is the most efficient to use friction wise.

I was thinking about the same thing. Since my Tow/Haul mode doesn't engage O/D, I'm about 50mph @ 2k rpms. If I were to install the new 3. 42 gears with a taller tire, I'd probably be in the 65 range @ 2k rpms. That's where I want to be. However, it might be doggish around town with tall gears and tall tires. That could be a mistake.

 

[Rams-n-Hogs]

4. 10's work perfect for me towing. I only use tow/haul in the hills, if the EGT's start getting high. Other than that, I tow in O/D. My RPM's are right around 2K@65, and most hills I can pull at that speed, or a little faster.

 

[Cattletrkr]

What's the big deal about 2K rpm?

 

[Rams-n-Hogs]

What's the big deal about 2K rpm?

That's the sweet spot on these engines.

 

[Cattletrkr]

So then just drive faster in o/d to get to 2000rpm.

 

[raychem]

The only ratios for the 11. 5 rear are 4. 10, 3. 73, and 3. 42... thats it. Now the dana 70'5 and 80's were from 3. 08 to 5. 36 I believe, so yeah there was more selection. To do what you want to do... run a smaller(not as tall) tire, it would be cheaper that changing a ring and pinion. You will need to run a 60 or 65 series tire to get you where you want. Or switch to 4. 10's and run an 80 series tire.



Richard

 

[trqmnstr]

I already have 265/65 and they look small enough. Any smaller will be rubberbands. I'm going to lift it and add some bigger tires so I'll need to change the rear or I'll really be in a bad spot. 2000 rpms is just a good spot for me towing... boosting just enough. Once I get past 65 or so with my enclosed trailer... it's just a waste trying to fight the wind resistance.

 

[trqmnstr]

What about some 4. 10 and some 295/70/17? Any idea where that would put me? Is there a gearing/tire calculator that will tell speeds, rpms, etc?

 

[bcpalmer]

I switched from 3. 73 to 4. 10 gears and went to B. F. Goodrich 285/65R18 tires. Now at 68 mph I am at 2000 rpm in O/D. This works well for me towing my 5th wheel.



Link to gear calculator:



https://www.turbodieselregister.com/forums/general-diesel-topics/89264-gear-speed-calculator.html