MalMac 1,328 #1 Posted February 26, 2015 I have got a 90 520H, It goes a lot faster than my 94 520H and faster than a couple of other hydros I have around here with the Eaton 1100. The drive pulleys are stock on it. I was wondering if maybe it might have got a HC hydro put in it at the factory. This tractor has not or does not show any signs of ever being messed with. Wonder if it possible that they had some left over HC trannys and one got put on this tractor to use up what was sitting on the shelves. Is there anyway to tell a HC rear end VS. what they put on the 520H's ? Share this post Link to post Share on other sites
slammer302 2,154 #2 Posted February 26, 2015 I've heard sum 520's got the faster hydro and sum didn't Share this post Link to post Share on other sites
bmsgaffer 2,043 #3 Posted February 26, 2015 According to the 1990 owners manual, the top speed should be 5.6mph Here are the other listed top speeds: I would get your GPS on your phone to find out how fast you are really going (i.e. make sure your 94 is actually reaching top speed). If you are going over that, then it probably had a replacement transmission at some point from an earlier model. Share this post Link to post Share on other sites
Callen 64 #4 Posted February 26, 2015 Is the RPM the same? Share this post Link to post Share on other sites
bmsgaffer 2,043 #5 Posted February 26, 2015 I am not entirely sure. No one that I have seen has measured the different hydro pulleys. There is a maximum speed on the eaton pump of 3600rpm. I assumed wheel horse either did a 1:1 or very close to that, but I havent measured. If they raised the diameter on some of them to slow the output, then that would be one way to raise the output speed slightly (without exceeding the maximum). As far as I know, speed changes were done with the internal transmission gears. I know there were at least two different types of rear end gearing, there may be more. Share this post Link to post Share on other sites
Callen 64 #6 Posted February 28, 2015 The rear tire roll out will effect top speed also. Share this post Link to post Share on other sites