In reply to "tractor moves fine. Just not much "low end grunt". Steers fine left but right, if I pull the lever and it is not full throttle, the dozer will actually stop."
Define "steers fine?" Steering has two parts. One is when you pull part-way back and the track stops getting power. Two - is when you pull back more and the brake-band engages and stops the track. Need more info. A 350B has dry steering clutches so engine RPM has nothing to do with them slipping or not. On the other hand - the reverser relies on hydraulic pressure to be adequate and that CAN get better with higher RPM if worn.
If your problem is "momentary" or RPM related - you can rule out worn/broken parts like splines and shafts. The best way to determine if your reverser is slipping is by what I already told you. You need to see if the ring gear is spinning when the crawler is not moving.
In regard to the steering clutches? Lock or hold the parking brake on. Put in 2nd gear, reverser in forward, and have both steering levers held back. Then slowly release the left one. It shoulde get to a point where the engine starts to labor and finally stall the engine as you release it more. If you fully release it - the engine is still running ( assuming the brake is holding) -something is slipping. Do the same test with the right and compare. If you want to just test the steering brakes - get on a hill steep enough so the crawler can roll in neutral. Let it roll and then try pulling back on either lever and see if the brake grabs on that side and locks up the track.