02 3500 dually 6sp NV5600 Rear wheel drive 3.55 ratio dana 80

 

Are you or do you know of anyone running 3.31 ratio gears in a dana 80? 

 

I'm currently running 3.55's and would like to switch to 3.31's so I can run lower rpm's in 5th (1:1) gear while towing.

 

If you have done this I would like to hear about what you think & how your truck is performing while running 3.31's.

 

Thanks!

Edited June 30, 20169 yr by Ironforger

what size tires?  

 

I plugged in stock tires to the gearing calc, and I can't see needing to get revs up in 5th if you have stock tires.  

 

 

32 minutes ago, Me78569 said:

what size tires?  

 

I plugged in stock tires to the gearing calc, and I can't see needing to get revs up in 5th if you have stock tires.  

 

 

I'm running stock tires 235/85 R16.

I'd like to lower my revs. Not looking to get rev's up.

 

Where can I find the gearing calculator?

 

Thanks!

click the link I posted above.  

 

What speed do you generally tow at?  What rpm do you see typically at that speed.

Lower RPMs will typically raise the egts, especially on hills.

Wouldn't a Gear Vendors be a better choice?

http://www.gearvendors.com/ag4x4.html

 

At least then you could shift of OD on top of the OD of the transmission and drop your RPM's.

 

How low an RPM do you what to run?  Towing at to low an RPM will cause the engine to "lug" and that may cause rod bearing damage.  If you're towing a trailer with ST tires the max recommended towing speed is 65mph.