Telehandlers are heavy duty work machinery made specifically to operate in rough terrain. This however, does not mean they could be driven without regard on rough terrain. These machinery have a a lot greater risk of load loss or tipping over when they are traveling on slopes.
If you do have to travel on a slope, make sure that you proceed slowly and carefully while keeping the load low. Prior to getting on the slope, downshift to 4WD and a lower gear. Using the engine brake would actually help to control the telehandler's speed. Try to avoid turning on a slope if possible. If you must make the turn, use extreme care and take it as wide as possible.
Under any circumstances, do not drive across excessively steep slopes. Descend and ascend slopes with the telehandler's heavy end pointing up the incline. Even when there is no load on the forks, the machine's counterweighted rear is fairly heavy; thus, it can be necessary to drive in reverse up slopes. When the telehandler is carrying a cargo, the front of the unit becomes the heavy end, and you could back the equipment down the slopes.
Operator training is hugely vital on a mixed jobsite. Rear pivot machines will usually operate on the same jobsite of coordinated steering machines, where everyone is permitted to utilize all of the equipment. In this case, an individual who is used to operating a coordinated steer machinery could jump onto a rear-pivot machine. A very significant distinction between how these two units operate has much to do with what part of the machine extends outside of the turning radius.