Hi, Total hydrostatic newbie here. I just bought a Litefoot snowcat with Sauer Series 90 pump and Volvo F11 motors. This is a low hour snowcat (1042 hours), with Chevron AW 32 being put in it about 30 hours ago. The problem is, that was five+ years ago. So my question is, does this fluid degrade over time, despite having very low hours on it? And, in your opinion, is Chevron AW 32 a good fluid to use with these pumps/motors? Thanks in advance. I initially posted this in skid steer, sorry for the x-post.
Typically oils have a shelf life of 7-10 years. With it being in your machine however it has been exposed to all different kinds of contaminants. The Chevron AW (antiwear) 32 your using is a pretty plain oil, its not expensive. I would definitely change the oil, if it were me I would flush it as well. Btw what part of Utah are you from?
I live in Sandy. Thanks for the advice. That's what I'm going to do.
Any idea of ATF Type F is compatible with Chevron AW 32? I've heard good things and lots of recommendations for ATF Type F in snowcats.
Nice looking machine!
Bombardier used type f in the 400, 400+ and ME,MP series of machines and maybe even in the BR350. they all ran the series 90 pumps and motors. For what its worth, Deere uses the series 90 pumps/motors in their dozers (450,550,650 for sure) and use 10w30 for oil
It seems like hydrostatic fluid choice is highly subjective, much like any debate for engine or tranny oil in the automotive world.
I'm not a mechanical retard (lots of experience rebuilding motos), but I've never worked on hydrostatic systems, so I'm looking for insight. Here's what I think one would do to flush the system. Drain reservoir Drain pump Drain hoses at final drives Refill process. Keep everything clean! Replace both filters Fill pump at upper access Fill reservoir Turn motor over with coil removed (30 sec) Repeat above step and check reservoir level Keep pressure gauge attached to M3 port, repeat above steps until spec'd pressure is obtained. Check reservoir level, fill as needed. Start engine, slowly cycle drives forward/backward for several minutes to remove air. Recheck reservoir level. Thanks for any and all advice.
If you intend to put some hours on it I would stick with hydraulic fluid, as it has better high pressure additives and can deal with free water batter than engine or trans oil. Universal tractor fluid/oil is even better at handling water, is meant to work with piston pumps/motors and "yellow metal", and is designed to be stored for long periods of time. You probably want an "arctic" or cold weather UTF, but there is not standard so watch the viscosity. FYI - ISO 32 is ~32cSt@40C The reason to use ATF is because it has a lot of viscosity improvers, so it works well over a wide range of temperatures. The bad thing is that these VI's are long chains of molecules that get cut up, a.k.a. "shear back". So over time the viscosity goes down. It also isn't designed to handle large amounts of water. You can use it, and it certainly has been used in OEM applications, but I would plan on keeping the service intervals on the short end of the recommended range. ISZ
Small world, I live in Sandy too. ATF has a more complex additive package, like Ice said it has viscosity improvers it also has friction modifiers. VI makes it less shear stable. The friction modifers make it have a limited slip action. Typically an AW oil has more demulsifier in it then ATF, separates water and oil better. If it calls for AW I would stay with it, look for a temperature guide for the viscosity grade.
Small world indeed. Want to come over to my house and help me change the fluid, or must give me the run down? I'd be willing to pay for your expertise. Or trade for some snowcat skiing in Snake Creek (Midway). I can rebuild car/moto/atv motors and transmissions, but I know nothing about HST.
Sure I can come over and lend a hand, might have to be next weekend. ill send you my number