It has been a long while since I was into a D3B, but best I remember it has dry steering clutches. The release bearing on each clutch tends to get to where it does not move in and out very well. When this happens, the steering clutch may be partially disengaged, causing the steering clutch to slip. The discs and plates in the clutch may be worn out causing it to slip under load also. Usually on these machines that release bearing which is a ball bearing that only can be installed one way due to the thrust, shells out causing the steering clutch to stay engaged when trying to turn, and then the brake stalls the whole machine to a stop or close to it. Maybe this can help you out. Good luck. :Banghead