Hydraulic, Live independent PTO of L4400

kgroesch · Mar 21, 2008

I am a new owner of a L4400-DT. I was out shredding some heavy yaupon brush and ran over too much for my Bush Hog SQ172 could handle. The engine RPM dropped considerablly but never stalled but when I looked back at the rotary cutter I noticed the PTO drive had stopped spinning. I lifted the rotary cutter up to free it back up and the pto shaft started spinning again and the engine returned to the proper rpm.

I guess I had expected that if the rotary cutter was ever bogged down that either the slip clutch would slip or the tractor would stall. Is this normal operation for a L4400 live independent hydraulic pto to not have a direct lock up to the engine? It sounds reasonable this may be expected operation but as I am new to this tractor I was hoping to get some confirmation that it is working properly.

simonmeridew · Mar 22, 2008

Hi K
I have the same tractor with a Farmi logging winch. I have stalled the engine out winching out a big heavy log that got caught behind a stump. I was not running the motor hard, maybe 1400 RPM, but I didn't get any slippage from the PTO like you described. The winch has a slip clutch, but I was pulling real hard on the clutch rope at the time and it didn't have the opportunity to slip before the engine stalled.

On another occasion, I have also have released the rope just as the engine was about to stall, and the engine started running backwards, an event which I described in the forum about 6 weeks ago or so here. An interesting anomaly. I shut it off immediately because no oil pressure with a reverse running engine.
simonmeridew

krackerjack9 · Mar 25, 2008

Got the same tractor and a Rhino 172 mower. I have stalled the motor cutting Wiesatch trees down.. some maybe a bit more than 3 inches or so but I push them over witht he loader then hit em with the mower. My RPM about in the 1600 range and it might be tow low but I dont have that many hours on it..I just keep the blades pretty darn sharp and it cuts great. Other than that I love the tractor burns a bit more fuel than the L3400 but im glad I got it.

kgroesch · Jun 6, 2008

Well I thought I would reply to wrap us this thread. Just got my L4400 back from being serviced at the local Kubota dealer. The dealer said a tube in the transmission had broke and that was why the PTO clutch was slipping. It was all covered under warranty but disappointing having this issue on my brand new tractor.

Soundguy · Jun 7, 2008

As you found out, the pto does not have a 'direct' linnk to the engine.. it DOES go thru friction media.(clutch). if your load is high enough to overcome the friction forces, and doesn't trip a torque limiter in the driveline, then it will either A, slip, if the engine can overcome the load.. or B, stall the engine if the engine cannot overcome the load.

soundguy