sounds like the slipper to me too....

http://www.youtube.com/watch?v=YW7can6WjRw

do the 6 screws on the bottom have to come out to get the rear diff out? if so it wont be possible cause 1 of the screws is stripped out.

page 10...

http://aedownloads.com/downloads/man...rtr_manual.pdf

only the 2 on the bottom when you attach the bumper too.

i took the 4 screws out and the rear part still didnt come off yet.

This is a opportunity to review the manual and learn the truck. If you do not know how to work on the truck then it makes it harder for us to assist you and find a solution.The B4/T4/Sc10 platform is very easy to work on. You have the 2 screws on the bottom, 2 under the rear shock tower, the tranny case and make sure you take the spur gear and plates off.

The plastic ones handle brushless just fine. My opinion is that this is unnecessary.
We don't even know exactly what your problem is yet
Exactly. What's the sound that it's making? Barking? Squealing? Moves barely or doesn't move at all?

it barely moves at all.

I have an SC10 RS that is totally stock. It really leans a lot going through corners and therefore spins out when I am at a high speed turn. How should I fix this?

If it barks, your diff is too loose and is more than likely toast.
If it squeals, your slipper is too loose. Tighten the slipper nut.
When you spin the wheels in opposite directions of each other(side to side), is there any resistance?

it sounds like a barking sound to me. what ever adjustments i made to the rear differential nothing changed. would i be better off just buying a new gear differential setup?

Start at the source of power and work your way to the wheels.
Motor
pinion
spur
Slipper
internal gears
diff
cvd knuckles
axle pins/hexes

The best way to learn about your truck is to just dig in and start taking it apart. Once you've done it a few times, it becomes easier and quicker. So if you happen to have an issue at the races, you can fixed it quickly.

I just bought a new factory team sc10 and will be running a 9.5T brushless motor in it. What pinion would be a good starting point for a small to medium technical track?

Thanks,
Matt

Try 20t and adjust from there.

If you're certain it's your ball diff, a gear diff might not be a bad idea. Gear diffs, for the most part, are bomb proof and easy to maintain. And most racers won't notice a difference in performance.