Aussie 98 #1 Posted October 6, 2014 I have a problem with the drive on my 520H mowing tractor. It starts off okay but the longer I am going the slower it gets, and it isn't due to the pump heating up. The direction control lever loses travel, it will not go into full forward position. It seems very tight, almost as if it is jamming at part travel. Some background - it has been happening for some time but is progressively getting worse. In an effort to solve the problem I changed the transmission oil and filter a few months back, used Mobil 1 and the level is ok on the dipstick, oil is clean and no discoloration. Pump and transmission don't appear to be getting too hot. I have had the seat pan and covers off, the linkage doesn't appear to be binding anywhere, all lubricated and moves freely with the engine off. A few times it happened I returned to the shed and turned it off, linkage went back to full travel straight away. Resume mowing and takes about half an hour to lose drive. So, yesterday I stopped the tractor when it started to get really slow. I tried for some time with the engine off but the linkage was still tight, it didn't free up at all. So I restarted, returned to the shed and turned it off again, lever freed up instantly! It also affects reverse travel, but not as badly as forward. I am wondering if it is possible for an internal leak in the pump to somehow pressurise the camplate? Other than that it has me stumped, would appreciate any ideas on what tests I could do? I have the Eaton manual and Toro productivity Series hydraulics but can't find any similar situation, other than the pump being worn out, which I don't think is the problem due to its ability to recover instantly (usually) after being turned off. Has anyone else come across a similar issue? I hope my description makes sense, happy to answer any questions on anything I have missed out. Any assistance much appreciated. Share this post Link to post Share on other sites
WH nut 553 #2 Posted October 6, 2014 Check the trans mounting to frame and also the top frame rail where the tank bracket bolts on. Mine was cracked at the trans and the top was broken off completely and depending how the frame flexed would cause the motion lever to bind Share this post Link to post Share on other sites
Aussie 98 #3 Posted October 7, 2014 Thanks WH nut, confirms a suspicion I had last night - it seems to go in easy after I get off. Not able to check it until the weekend, but I would be happy if that is the cause, an easy fix compared to a transmission rebuild. I did look under recently but must admit I was focussing on the bottom trans bolts which didn't show any cracking around, will have a look higher up. thanks again. Share this post Link to post Share on other sites
WH nut 553 #4 Posted October 11, 2014 Find anything yet? Share this post Link to post Share on other sites
Aussie 98 #5 Posted October 14, 2014 Not yet, can't see any obvious cracks, bolts appear tight, but I think you have nailed it. Will have to take the seat and pan off, it must be flexing up top somewhere. I had to use it for a while on Sunday, got really bad - lost almost all forward drive. Stopped, still wouldn't go all the way forward. Got off, instant full travel. Back on, reversing alongside shed, mower caught on footing, jerked tractor - instant full forward drive so there is definitely something moving around underneath. Will not be using it again until I work it out, going away this weekend so may not have time to pull down but will post my findings. thanks again, I am much happier knowing it isn't a transmission problem, don't have any problems with welding or fabrication if that is necessary. 2 Share this post Link to post Share on other sites
Aussie 98 #7 Posted November 12, 2014 Well, I am perplexed. I pulled the seat and rear pan off on the weekend and everything seems to be tight and as it should be. There isn't any damage to the back of the console upstand where the front of the seat mount / fuel tank support bolts through. The four bolts from the frame to the transmission are all tight. The frame is reinforced with a heavy steel plate in this area, not sure if it is factory as it is heavier than any I have come across before, but it doesn't appear to have been repainted. No sign of any cracks anywhere. I will take the mower deck off when I can make some room and get a better look underneath, but at first look nothing seems amiss. Share this post Link to post Share on other sites
ericj 1,576 #8 Posted November 12, 2014 not sure if this would be your problem or not ,but i know that sometimes my hydro tractors won't go full speed and you reach down and pull the brake pedal all the way back with your floor and then the mcl or mdl will move full range hope this help and good luck eric j Share this post Link to post Share on other sites
WH nut 553 #9 Posted November 13, 2014 I thought for sure you would find some cracking Share this post Link to post Share on other sites
