9" gear strength by ratio?

RustyC · Jan 23, 2015

Looking to regear. Low HP V6 engine and NP205 = I need lower ratio gears.
Current setup is 38" tires and 5.13 gears. Rear engine and axles are flipped. I and driving on the weaker coast side of the gears.
I know this adds up to not exactly the strongest setup but it is what I'm dealing with.

Looking into a 5.83 gear with a 35 tooth ring gear and a 6 tooth pinion
or a 6.00 gear with a 30 tooth ring gear and a 5 tooth pinion

of those two what would the stronger ratio and WHY?

InDaShop · Jan 23, 2015

the 5.83 is stronger. less pressure per tooth.

matth_85 · Jan 23, 2015

^^ yes. The contact patch is greater on lower (numerically) gear ratios. More engagement=stronger.

Technician · Jan 23, 2015

Change the t- case gears and leave the axle gears alone

RustyC · Jan 23, 2015

Technician said:
Change the t- case gears and leave the axle gears alone

I recently swapped a Dana 300 for the NP205. I could swap it back but I like the feeling of not worrying about broken output shafts. The Dana 300 has stock outputs front and rear.
Gearing with the Dana 300 was a little low. To get the same final drive ratio as the 300/5.13 combo I would need to run the NP205 and 6.83 ratio in the axles.
I am hoping that keeping the NP205 and using a 5.89 axle ratio I will performance in the rocks without being to low like the Dana 300.
Plus a pair of 9" gear cost less that Dan 300 output shaft not even considering the labor.

I would love to just swap the 4.3 V6 for a L33 5.3L. Losing weight and gaining HP but that is not an option right now.

matth_85 · Jan 23, 2015

Gear the case. Big axle gears are not the way to go IMO.

RustyC · Jan 23, 2015

matth_85 said:
Gear the case.

I agree that would be best but I run a Ford 205 so no Low Max gears for those. Stuck with a 1.96-1 low range.

I think I will be giving the 5.83's a try soon 35 spline pinions would be nice but more $$. An LS swap may happen in the future but for now gears will have to get the work done.