I am on Mazdatrcuking.com and a member there posted this:

I told him that I dont think a RX8 rear Diff would be as strong as a Mazda truck or Van rear Diff. My view is that the RX8 is designed to go fast, and not designed for any sort of abuse ie: 4x4ing, hauling, towing etc. all the things we do with a truck..

I've had him pretty much tell me that I'm full of crap, and had others climb onboard his post, and tell me not to start a "pissing match"

So I figure that you guys would know best..

WOULD a RX8 rear diff handle the abuse that a Mazda truck would throw at it..

 

It will.

 

What are HP and torque specs of comparible engines?
Chances are RX-8 is higher, therefore, RX-8 driveline parts should handle it.

 

Horsepower doenst come into play when you are clawing your way through mud, or crawling up rocks. It is bottom end grunt you want..

Performance
Horsepower: 121 hp @ 4600 rpm
Torque: 149 ft-lbs. @ 3500 rpm

When I am crawlin or mud slinging I rarely leave 1st gear.

 

RX-8 specs: Power (SAE): 232 hp @ 8,500 rpm; 159 ft lb of torque @ 5,500 rpm

So the RX-8 unit can handle the Torque.
However, what you're talking bout is final gear ratio.
A final gear ratio of 5:1 is better than 3:1 when rock crawling!

Just found final gear ratio for RX-8 : 4.77:1

Don't ask me what year those specs were from!

 

5500 RPM the engine is screaming.. What is the FT of TQ @ 3000 RPM??

I'm not sure what the gear ratio is on the 4x4's

 

It doesn't matter what rpm torque is at, we are comparing diff's not engines.
THE RX-8 diff can handle torque.

Rock crawling is about slow-speed, careful and precise driving, and high torque generated through large gear reductions in the vehicles drivetrain.
rock crawlers typically lower their gear ratios in order to drive more slowly over obstacles without stalling the engine.
So it is all about gear ratios and if diff can handle it.
The diff in question is comparable to yours, but what about actual gear ratios in the transmission! This is the difference in successful crawling.
Done!