i have 3:73 open differential in my truck and i was wondering if power is ever applied to both wheels, or if the right rear was the only wheel to ever get power...if so when or how is power applied to both wheels..

I don't know how it physically works inside but I can explain what it does. If there is even resistance on both wheels, both will get even power. If both wheel are for example on ice, the right wheel will be the one to spin. If the right wheel is on solid ground and the left is in snow or ice, the left one will spin. If one wheel has 70% traction and the other has 30% traction, the power will be distributed accordingly. This setup is great for average highway driving, but off-road or in snow, it SUCKS. I wish I had a limited slip diff instead of the dumb open one.

Matt

Check this (http://www.howstuffworks.com/differential.htm) out. It's very informative.

Originally posted by FireRanger
If one wheel has 70% traction and the other has 30% traction, the power will be distributed accordingly

Actually, both wheels will get the same amount of power at all times...The amount of power sent to the wheels is based upon how much power the wheel with the least traction can handle before it starts to spin...
The reason for the dreaded (and "geeky") "one-wheel peel", is because the amount of power that is needed to cause the right tire to spin also gets sent to the left tire...And, this amount of power is not enough to get you going in any big hurry...That is why you will kind of creep along while your one tire is spinning like crazy...
Quick example: Your engine can put 200 lb-ft to the ground...You park with one wheel on solid (high-traction; asphalt) ground, and the other in gravel...You give it some gas...The tire in the gravel requires only 70 lb-ft to start spinning...70 lb-ft is also how much is sent to the wheel on the solid ground...So, you are putting 140 lb-ft to the ground, but because 70 is being spun away, you effectively are only getting 70 to move your truck...This is why l/s and lockers are so helpful...With a locker, if your truck can put 200 lb-ft to the ground, and you are parked in a similar situation...200 lb-ft will be sent to all drive wheels, regardless of the traction situation...In the above situation, you now have 200 lb-ft to get you going...
If both wheel are on solid ground, it is basically the same, but it will take more power to get the low traction tire spinning...With lockers in this situation, the math for the above engine works as follows: If you have a two-wheel drive, you will get 400 lb-ft to the ground...With a four-wheel drive (in 4wd, with lockers both front and rear; not recommended, FYI), you will put 800 lb-ft to the ground...
(ok, it wasnt so quick after all)
Blah, blah, blah...Im tired...