moe1965 744 #1 Posted August 16, 2019 Hello all. I'm new to hydraulic or auto transmissions. So please forgive my ignorance or how I might explain the issue I'm having but here we go..... the trans seams to work fine when I first start mowing but the forward motion slows down as the oil in the trans heats up. It has power to climb hills but with the leave all the way forward it responds slow. Any thoughts the fluid is old but at the full mark. Thanks in advance. Share this post Link to post Share on other sites
bc.gold 3,403 #2 Posted August 16, 2019 (edited) Which model of tractor, this will tell us the model of the hydro used. Loss of power when hot usually indicts worn internal parts, when the tractor is cold transmission oil is much thicker and is able to close up the gaps in those worn tolerances. You might get by with just a filter and oil change, oil looses it's quality's with age. Edited August 16, 2019 by bcgold Share this post Link to post Share on other sites
moe1965 744 #3 Posted August 16, 2019 (edited) It's a 1967 1277 I just acquired this tractor from the original owner. He stayed he never did any thing with the trans such as oil change and filter. I would agree with his statement because the filter is very rusted and probably original. I'll change fluid and filter and see if it improves. Any idea on filter replacement number and or brand. I'm not able to see a number or brand on the filter on it now. Edited August 16, 2019 by moe1965 Share this post Link to post Share on other sites
pfrederi 17,881 #4 Posted August 16, 2019 Wix 51410 What color is the fluid. Red is ATF(dexron 3) tan Motor oil (10w-30) use what ever was in there. Share this post Link to post Share on other sites
moe1965 744 #5 Posted August 16, 2019 Red fluid. I will change both fluid and filter this weekend and report back. Thanks Share this post Link to post Share on other sites
bc.gold 3,403 #6 Posted August 16, 2019 If the hydro needs more than an oil change the repair manal is located here. https://www.wheelhorseforum.com/files/file/24-transmission-hydro-sundstrand-sm-492-4206pdf/ Diagnostic chart from the repair manual. Share this post Link to post Share on other sites
bc.gold 3,403 #7 Posted August 16, 2019 (edited) Save the oil you've drained from the hydro thin it out with a solvent of your choice. Let the oil settle out over night then carefully decant into another container. Examine the metal particles that settled out, these will be on the bottom of the container used to dilute the oil, take a magnet and remove anything magnetic. Hopefully you'll not see any brass. I usually open up the spent filter to see if any metallic's and type have been captured, the heavier bits if any present will come out when you drain the oil. Edited August 16, 2019 by bcgold Share this post Link to post Share on other sites
daveoman1966 3,762 #8 Posted August 16, 2019 What you've described...."ok at start up, then gets slow / sluggish" is typical sign that the Sundstrand pump is crying for an overhaul. This is NOT difficult to do, but take a meticulous effort to get it right. There are brass components inside the pump that easily scratch or score from contaminated fluid...ATF or Motor oil.... Whats more, it is 50 + years old and things just plain wear out. I have a MS Word narrative---with pics----that can help you thru the overhaul. Do you see any leaks around the pump ??? After 50+ years, seals MAY need replaced...or should be. 1 Share this post Link to post Share on other sites
moe1965 744 #9 Posted August 17, 2019 I drained the fluid today and I did see flakes in the bottom of the pan. Not as much as Parker on season 2 of gold rush but enough to make me think of rebuild but not sure if I'm up to the challange. I cut the filter apart and didn't see anything unusual The oil did smell a little off so I might just replace filter and oil and see if it gets better. 1 Share this post Link to post Share on other sites
bc.gold 3,403 #10 Posted August 17, 2019 4 hours ago, moe1965 said: I drained the fluid today and I did see flakes in the bottom of the pan. Not as much as Parker on season 2 of gold rush but enough to make me think of rebuild but not sure if I'm up to the challange. I cut the filter apart and didn't see anything unusual The oil did smell a little off so I might just replace filter and oil and see if it gets better. Really fine brass particles contribute to years of normal wear, flakes of brass could mean one or more piston slippers are broken or nearing total destruction. The other brass found inside the hydro in on the valve plates which generally score. The plates maybe resurfaced by lapping. These hydro's can not be bench tested because they dump the oil back into the transmission housing, and have to be tested while installed in the tractor. I suggest you browse the repair manual find the test section then hook up a pressure gauge to the test port on the hydro. The expected pressure limits on the test ports will be in the manual. Share this post Link to post Share on other sites
