2006 Rtv 900 hst issues


New member
Ok so I have a 2006 Rtv 900 with slow to no power does a little better in 4wd. Local dealer will replace complete trans. With the hours 3900 it's not worth the price. I'm assuming I have hydraulic pressure issues as many have experienced. I'm fairly competent in repair as it's what I do although on appliances not hydrostatic transmissions. I also have 6 of these on the farm and prefer the older models because of the medium range. What is a good hydraulic pressure test kit and how involved is replacing the plates that I see people post on. The unit still runs well and floor and overall condition is decent. I don't mind spending some money on the unit just not the 7k for a new transmission. Im located in central va in case anyone is a rebuilder of the hydro units.


Well-known member
SUPER Site Supporter
First thing to consider… that the unit is using only Genuine Kubota UDT or SUDT2 hydraulic fluids. ANY OTHER fluid is unreliable and causes slipping and low power issues.

The WSM describes the process of repairing and rebuilding the HST. (I don’t have the need or courage to try but others here have done so quite successfully and hopefully they will chime in.)


Well-known member
Site Supporter
First confirm that your engine rpm is in spec and that the linkage is adjusted in spec and fluid and filters are oem sudt2 no aftermarket. Before you assume the hst is at fault. Then confirm charge pressure is at spec and if it isn't adjust it or repair the charge pump and re test. And from there you can proceed. There are no clutches to slip,only flow and pressure.