the vibration may be cavitation which will cause heat and severe damage if not corrected, of course, cavitation is likely to cause a whining, jerking, sputtering feel in the hydraulics as the system continually trys to purge air fom its pump, lines and motors. Check the oil temp after an hour of use, hydraulic oil (aw46 or equivelant) is ok to 200 -250 degrees but over that number would not be the best case for your pump. Engine oil does not do well over 200 degrees long term. I ran my 825 6 hours and tested the oil temp with a remote probe on my DVOM, just pushed the little rice sized sender down the hydraulic fill tube, my oil never once was over 160 degrees and I have to say I was using the machine but not abusing it!!??!!?? My machine when traveling fast or slow in a straight line is perfectly silent, when I turn it whines the same left or right but its not much different than my friends ASV or my neighbors Kubota or Cat skidsteer. I don't worry about it, it's fully serviced, new filters and oil. If it doesn't scald the oil I agree, it's not far from normal. But if your oil looks milky or foamy its a sure bet, you may have cavitation(or water) but most likely its air leaking into a suction line of the charge pump or main pumps causing the system to be randomly filled with pockets of air. If the oil gets hot quickly you need to find the problem quickly By the way the ASV and Kubota are new, less than 100 hours while my 825 is 30 years old. I hope some of this helps, jeffco
