oldhorse2 3 #1 Posted May 26, 2016 Last fall I swapped the original (leaking) transmission with one of the same vintage...both Sunstrands. It has performed well plowing snow, hauling and mowing...until today. After extensive mowing I noticed a loss of power on steep inclines (which have not been a problem previously). I changed the oil (10w40) and filter last fall, and the oil level was correct today, although the oil seemed very hot and thin. The tractor sat for a while and cooled down some, and when restarted it seemed to perform better but still not up to previous performance level. Any suggestions on where to start with this problem will be greatly appreciated. Share this post Link to post Share on other sites
daveoman1966 3,586 #2 Posted May 26, 2016 The symptoms you descdribe....gradual loss of power as the unit gets to operating temp... is precisely what happens when the hyd PUMP and the hyd MOTOR become worn out. The only long-term solution is a rebuild of the PUMP and the MOTOR. The motor is bolted to the side of the transaxle. To rebuild one and not the other defeats the rebuild process as the internal parts are almost identical. Brass components of each become scarred and scratched at machined surfaces. Then warm oil escapes thru these scratches, resulting in a loss of pump pressure, leading to loss of power. I have rebuilt many of these and I have one on my bench now that I just finished the rebuild. It is from a C-120 of your vintage and should bolt right in. If you'd want to purchase this unit from me, send me an off-stie email....(outside of this forum). my email is: daveoman@windstream.net 3 Share this post Link to post Share on other sites
Thisguyisnew 114 #3 Posted May 26, 2016 I would agree, But Is it acting better without mowing or a load applied. I have a c-160 hydro and the only time I had some problems with slowing had to do with the sensitivity on governor spring adjustment. Never touched when I got and only acted up a while after I cleaned carb... don't know why that was but adjusting sensitivity solved the problem. Share this post Link to post Share on other sites
squonk 38,844 #4 Posted May 26, 2016 Do you hear the engine labor as well as the trans? If just the engine bogs it could be a worn out motor. If both the engine and trans makes noise, I would say it's what Dave described. My C-160 lost power and the engine would bog down and the trans started whining at the same time. I had to replace the trans to fix it. Share this post Link to post Share on other sites
oldhorse2 3 #5 Posted May 26, 2016 This power loss became noticeable after 1+ hours of mowing, as I was attempting to climb a grade. I switched off the pto to stop the mower and reduce the load, and was able to climb a bit better. There was a definite whine coming from the trans.when all of this was happening. Share this post Link to post Share on other sites
daveoman1966 3,586 #6 Posted May 26, 2016 The unusual WHINE is common to worn out pump....but you need to have the motor rebuilt too for reason stated earlier. Again, I have the rebuilt unit available now. Send me an off-forum email for details: daveoman@windstream.net Share this post Link to post Share on other sites
