Need Help....Groundsmaster Hydro Problem

I have an older 1995 Toro Groundsmaster 223-D mower that I use only on my personal property. Even though the mower has some age on it, it has been well taken care of and serviced regularly and is in quite good shape for its age with the exception of one problem.
The problem, I think is in the hydro system. The mower act like the hydro fluid is low while I am driving on level ground or going down hill. It will pull for 20 to 30 feet and then it acts as if there isn't enough fluid for a second or two and then it will start pulling again for another 20 to 30 feet. This process continues as long as I am on level ground or going down an incline but NOT up hill. It does seem to run just a little bit better after the mower has run 30 to 45 minutes and gets good and hot. This problem has been going on for at least a year. The mower is operational and I can mow with it but it is starting to get on my nerves if you know what I mean.
It doesn't do this at all when I am climbing UP a hill. It will climb just about any grade of hill with no problem whatsoever and it doesn't do this while driving in reverse either. Just going forward on level ground or down hill. The fluid and filter only have 17 hours on them.
From my little experience with hydro drives, usually most problems occur when trying to go UP a hill...not down a hill.
Any Ideas at all?????

 

It sounds like a worn axle key/hub, Jack the unit up and grab the tire checking the wheel hubs to axles for any rocking back and forth.

If the hubs are tight on the axle then gander at the things listed below that apply to your unit;


First check the belt for looseness, Check the dump valves for being closed all the way. Then all linkage for wear/slop including the lever on the pump shaft. Check all hydro hose fittings for being tight, One could be sucking air but not leak oil.

 

I have already checked most of these things. The wheels are tight on the axles with no play at all. Also, hydro unit is powered by a driveshaft and has no belt. The linkage is tight with no play. I'm not exactly sure what the dump valve is, but if it is the valve that you move to be able to push or tow the mower, I've already checked and replaced the o-rings in it. I can't understand why it pulls hills or drives in reverse with no problems at all. I was wondering if I could somehow change the hose from the reverse side over to the forward side. I wouldn't really care if it acts up in reverse since I rarely use reverse.

 

Hydro Service
202 N Main St
Roland, IA 50236
515-388-4096

Call this man and visit with him he is an expert and learned his trade at the plant where your Hydro was built in Ames Iowa. He can repair an Hydro and is as reasonable as any and he can be trusted. I have used him many times. I just boxed it up and sent to him he fixes it and sends it back.
Better yet he is small town Iowa and will tell you everything over the phone so call him first.

 

Thanks sooooooo much for that info. I called that number and spoke with Dan. He talked with me for at least 30 minutes and knew the excat Hydro pump I have down to the smallest part. He took the symtoms I described, then started started ruling things out. After all was said and done, he believes that one of the Part#'s 49-7830 is either worn or has some debris trapped in it. He said that is just about the only thing that could cause the unit to act up like that when not in a hard pull. Most anything else wrong with the unit wouldn't allow it to climb hills like it does now.
Thanks Again....

 

Hey when you get as old as dirt or as I am experience does start to pay off. Makes me feel good to have at least been a small part of a success today.