HST Shudder

b8200hst4wd · Jun 30, 2002

After mowing for about 30 min with my RFM the HST on my b8200 begins to shudder and the revs drop to about 2000rpms...

Let up on the pedal wait for it to come up to speed (10 secs) then keep mowing go about 250 feet happens again....

Fluid is fine... Range doesn't matter H,M,L

It's is due for a fluid change but i've never had this happen with my MMM could it be that this tractor is about to bite the dust or maybe the filter is plugged...

Have any of you had this problem when it is due for service...

I'm hopeing its not a big problem like a plugged port...

ns_in_tex · Jun 30, 2002

Don't know the answer to your problem, but it got me to thinking so am throwing out my info to see if it stirs up anything for either of us.
I have an L4610 HST. Service mgr told me he would be concerned about hydraulic oil temp if I added a hydraulic motor powered mower, so when I did I added an indoor outdoor thermometer with the OD sensor taped & insulated on the HST filter, so I could watch the oil temp.
I designed the hydraulic motor so I could run the tractor engine around 1500 RPM. I never saw the temp rise above 140 degrees like this.

Now when mowing with a 6' rfm on the pto & engine rpm above 2500 rpm, the temp climbs above the 158 degree max range of the thermometer.

I understand hydraulic oil starts breaking down in the 200 degree range.

Also could you have a stopped up oil cooler/filter/strainer, ETC?

Just food for thought.

ELsigundo · Jun 30, 2002

on the right side of the transmission, there is a metal hydraulic line, it has a banjo fitting where it goes into the trans case, there is a big nut on the outside holding the line in place. the nut is a strainer/filter. pull it out and clean it. try that first

Soundguy · Jul 1, 2002

Anyone ever add auxiliary oil coolers to their tractors? Plumping shouldnt be too hard depending on how your suction side is setup.

Soundguy

smthng2do · Jul 1, 2002

Before you go taking the tranny apart, make sure that it is not in your mower. Perhaps you are low on oil in the transfer box, or that an idler is not going bad, and when it heats up, it is binding and killing the engine. I would definately start with the deck. If it is only happening with the PTO engaged, I would think it is related to that, and not the HST. Bearing seizing in the idler, or the bearings in the gearbox locking up on ya. If that's not it, then I would do the tranny service. Clean the rock filters and replace the HST filter as well.