New Member here. I have a new to me RTV900. PO said he smoked the transmission pushing a truck. It then sat unused for several years. When I got it, it wouldn't move. I drained the transmission. Fluid was nasty, ,had been contaminated with water. I soaked the transmission for a day with kerosene then drained that. I opened up the hydrostat and the brass valve plates were toast. The pistons in the pump and the motors were stuck. I got everything free and clean and replaced the valve plates. I got it buttoned up today. It drove great for about 15 mins. As the transmission warmed up it started losing power to the point it would no longer pull itself. I'm looking for a direction to go next. Thanks!
RTV900 Transmission problems
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Runs With Scissors
Well-known member
Equipment
L2501 TLB , Grappel, Brush Hog, Box Blade, Ballast box, Forks, Tiller, PH digger
I don't have any experience with one, but is a new/used transmission available?
Or, is your mind made up that you want to rebuild/fix it?
Just wondering.
Or, is your mind made up that you want to rebuild/fix it?
Just wondering.
Many times you can find things on ebay. Kindly see the photo below.
I'm not sure what parts you are referring to however.
See the photo from Messicks below also
I'm not sure what parts you are referring to however.
See the photo from Messicks below also
New transmission is cost prohibitive. The mechanical parts of the transmission are okay. It's something in the hydrostat unit. Those parts are available and affordable. I believe the repair will be do-able once I get it narrowed down. The Kubota WSM troubleshooting tree is somewhat lacking IMO.
I would do some basic pressure testing before tearing into it. From my experience with these you generally can work around driveability issues with leaving the unit in tact without disassembling everything.
Checked charge pressure today. Gauge reads almost zero at idel. Full throttle gives me ab out 40-50 psi. Book calls for 75-104psi at full throttle. I pulled the back apart to check the poppet and spring on the charge relief valve. Looks okay. I took the high pressure relief valves out and cleaned them. Put it all back together. Same problem. Low charge pressure. Machine will drive around but feels "weak". When it gets up to temp it wont move. The brass valve plates and cylinder assys of the pump and motors still look okay. I haven't been able to find in the manual if the pressure relief valve bleeds charge pressure. I'm trying to rule out everything possible before the charge pump. You have to remove the transmission and completely disassemble it to access the charge pump. Ugh. I did drain and and change fluid again today. That makes the third time I've drained it trying to get all the nasty out.
It's a safe bet that the reason your charge pressure is low is because something else in the hydrostat is worn and allowing charged fluid to pour out of the circuit.
Sunstrand published an article about how charge pressure was a reliable indicator of hydrostat component wear/damage.
Sunstrand published an article about how charge pressure was a reliable indicator of hydrostat component wear/damage.
I finally got back around to working on it. I replaced the high pressure pump and it's valve plate. I also opened up the top of the transmission for a look. It was full of mud! I washed the tranny out with kerosene. Buttoned it all back up and it works like a champ. I've put about 15 hours on it. I'm going to change the fluid and filters one more time and call it good!