Has damage been done?

[redrocketship]

I have a MX5100 HST 4wd that only has about 100 hours on it. The other day my boy used the tractor and put it in High gear and drove around for a while (without permission mind you). Anyway, he said that when he would go up a rise, the tractor would slow down so he pushed the pedal down further and he said it was like a clutch was slipping. He said a couple of times it almost stopped. My question is, did he do any damage to the HST system? I used it yesterday and it seems to be making more noise than it use too. Is there any adjustments or anything I need to check?

 

[North Idaho Wolfman]

I have a MX5100 HST 4wd that only has about 100 hours on it. The other day my boy used the tractor and put it in High gear and drove around for a while (without permission mind you). Anyway, he said that when he would go up a rise, the tractor would slow down so he pushed the pedal down further and he said it was like a clutch was slipping. He said a couple of times it almost stopped. My question is, did he do any damage to the HST system? I used it yesterday and it seems to be making more noise than it use too. Is there any adjustments or anything I need to check?

Nope he didn't do any damage ( don't tell him I said that, use it for ammo later ), it just got worked, that's normal for an HST to do exactly what it did, does the same on my HST.
I think the "noise' your hearing is just a nervous reaction to the possibility of something being wrong.
Check the fluid levels and if it's still making noise It might just need a fluid and filter change, if he ran it harder then you normally do he might have just stirred up sediment in the bottom of the cases and that has restricted the filter, causing more noise than normal.

 

[Billdog350]

+2 on Wolfman's comment. That is what HST's do. Most machines, including the big M tractors don't really have power to pull any sort of hill in high range, especially if you have a load on back or in the bucket. Think of high as a transport gear, used for heading down a road, nothing more. Fortunately like wolfman said he likely just heated fluid (very doubtful he hurt the fluid, let alone the tractor itself). One thing to note too is that the HST's like a pretty high rpm to work best. Idling or a bit off idle will NOT work well with an HST especially in high range. If your son didn't have the rpm cranked to the moon, that totally explains why it wouldn't take the hills in high range and the machine almost stalled out.

Use it and enjoy it! And give your son a nice verbal lashing about the price of a new hydrostatic motor (over $5k) that he could have cost you.

 

[hodge]

The HST will have a bypass valve- too high of a load with not enough power or too high a speed for the load imposed will utilize the bypass. That is probably what he was experiencing when it felt like a clutch slipping.

 

[Butch]

You guys are dead spot on... the max pressure prior to engaging the pressure relief valve... my max pressure is 1991 PSI... this keeps us from screwing up big time...