Pow'r Max Hydostatic Drive Issues

[PaulSJr 0]

I have a Simplicity Pow'r Max 4041, with an Onan 19.5 engine. It has Hydostatic Drive and a 3 speed transmission. My problem is the Hydrostatic transmission control lever only works in reverse. Before i change the clutch belts, Trany fluid, oil fluid, also with the correct filters, the tractor only creep in reverse but not forward. After i change the above items, it then hard a very strong reverse but still no forward. I also after changing trany fluid and filter i prime the trany. I could not do a pump pressure reading. I am looking for some suggestions on what to try next. I have consider taking the hydrostatic Drive out and rebuilding it. Which brings up another questions , Do they make a rebuild kit for this hydrostatic transmission if so where would i go to purchase one. Any assistance would be appreciated. Thanks in advance and Happy Holidays.

[isetta 50]

Paul, pull the frame top cover and look to see if the shaft at the bottom of the hydro lever moves as it should when you move the lever back and forth. I am no expert on these but have done a lot of reading and will send you a nicely written overhaul document. I have one with a similar problem

[720nut 4,225]

If you have 3pt does it work? Johm (midnight pumpkin) is the man to ask he will probably chime in to help just my .02

[Rigger9020 13]

I won't start or run the tractor at all until you check it out! Those hydros have a issue with the roll pins that hold trunion shaft to the swash plate breaking and working loose inside the pump side. The broken pins will push through the case to motor side and do some serious damage. I had this happen, wasn't cheap to find replacement parts. With both top and covers removed move control lever back and forth check to see if both sides of trunion control shafts move together. I suspect that the pins are broke and you can't move swash plate to forward position. (Mine stuck in forward, had no reverse)There is a chance you might have a stuck control valve. Either way I would recommend pulling hydro and breaking it apart. They are not that bad to work on. When you look for parts the tag on the hydro says like series 90? But to find parts you need to look for series 21? Can 't remember off hand will check my receipts and get back on that. The series 90 tag was used only for garden tractors, but is same unit.

Good luck Mike

[isetta 50]

Paul, I sent you a PM but could not attach the article so here is the link. I thought this was very well written so saved it and saved all the pics to insure I would have it when I tear into mine. Hope I do not offend anyone by link to another GT site during this time of Microsoft induced attachment dilemma

http://gardentractortalk.com/articles.html/_/tech-tips-how-to/sundstrand-series-15-inline-pumpmotor-rebuild-r147

[Rigger9020 13]

That's a nice article, wish I had that info couple years ago! Isetta right series 90 is same as series 15.

Mike

[isetta 50]

Also found tech and service manuals for these

http://www.flinthydrostatics.com/pdfs/Sundstrand-Series-15-Service-Manual.pdf

http://inspectapedia.com/heat/Sunstrand_Txmsn_Manual.pdf

[PaulSJr 0]

Well it looks like I have my work cut out for me but with this information I feel better in taking this apart. I need to thank you all especially isetta for assisting me with this and all of the Manuals. I will keep you in the loop when I get it done. Any suggestion where I might get parts or a re-build kit?

BTW the PTO works and the shafts are moving.

[isetta 50]

Paul, Rigger has a good point to check: "With both top and bottom covers removed move control lever back and forth check to see if both sides of trunion control shafts move together"

This can help diagnose the issue before you take the unit apart. If they move together like Rigger describes then likely the trouble is elsewhere. If they don't rotate one to one together then likely the issue is with the pins holding swashplate to shaft.

[midnightpumpkin 83]

Did you check for slipping drive belts?

John U

[720nut 4,225]

Hi Paul,Welcome to the club, we're all wondering if you got problem diagnosed? I recently had my 620 not wanting to move, turns out I stretched the new belts when old hydro was seized and they just slipped on the new hydro ( special thanks to John for helping me find problem) Readjusted clutch and everything works as should be, I'll have to replace belts shortly but we'll run this way till no adjustment left and then replace

[PaulSJr 0]

Sorry for not responding right away. I work in a mountain resort and Christmas is very busy with skiers. As soon as the resort slows down I will dive into the trany, meanwhile, I did replace the 2 belts and adjusted the belts. What I did notice is the hand controls that are connected to the side of the Hydrostatic trany, the shaft moves in and out of the trany 3/8 to 1/2 an inch of play. So when I take it apart I will focus on why their is so much play in the shaft coming out of the right side of the trany. Hope you enjoy the Holidays

[isetta 50]

Isnt' that always the thing, dang work keeps getting in the way of the good stuff..... If the hand control is the lever to control forward and backward movement of the tractor then it sounds like the pins are loose or fallen out of the swashplate. I would recommend not to drive it and put new pins in it as soon as you can.

[Rigger9020 13]

Paul,

I understand how that work thing gets in the way, just worked 16 days in a row before Christmas. That amount of side play in trunion shaft is not good. I checked my spare hydro and it has less than 1/8". There are c-clips on both sides that control side play of trunion shaft. Sorry but looks like you have broken roll pins. Hopefully they stayed contained in shaft/swash plate.

Mike

[PaulSJr 0]

so i finally got the Hydrostatic unit removed and torn apart. I found that one roll pin was broken on the swash plate/trunion shaft. Does not look like any damage inside, also found the drive pin in the charge pump was broken but had not fallen off. I called small engine parts warehouse and found out that they discontinue that seal repair kit #1685044, so the question is where might one find a seal repair kit for the unit? Any help would be appreciated. Thanks