4400 running backwards

[curtisfarmer]

Can't the machine in theory feed itself with oil getting past the rings and into the pistons? I guess that assumes an older, worn machine. I have heard of it numerous times, usually with dump trucks, but never seen it. I have heard about the oil getting past the rings and not being able to shut it off, needing to stall it again before the motor is toasted.

 

[unit40]

I have had this happen to me on two occasions that I can remember. The first time was with a Ford F7000 dump truck with a 3208 Cat engine, standard transmission, and mechanical PTO to the hydraulics. As I was dumping out a load of grass and leaves, with the body up, I tried to move the truck and hit the brake to shake the load loose. I think what happened is as the truck stalled at the same moment the dump body came forward, pushed the piston and for whatever reason after that, black smoke came out of the hood, engine running funny etc..Mechanic said it ran backwards.
Second time was with a gear drive JD1070 tractor. I wasn't paying enough attention while fertilizing a park area and ran into a tree with the front loader. Tractor bounced back and started running backwards while the tranny was in a forward gear, all the while dash light on and rough sounding engine noises. I knew right then what happened.

 

[art]

Any mechanical fuel injection system with a gravity feed fuel supply will run. A neighboring dealer took in a Same Tractor a nuber of years ago. While loading he drove on to the roll back and shut the tractor off in gear to hook the winch. He then went to tighten the winch cable on the tractor and tighten the chain when the rear chain came off and the winch speed alone started the tractor and it drove over the front rack of the bed into the cab before it lost enough power to stall.
I would think that the 4400 should not have started in reverse on the pto. I do believe something is wrong with this to happen.

 

[john_bud]

The L4400 has an independent PTO so it is not tied to the transmission. There is probably not an ORC since the PTO is tied directly to the engine. I suspect that the incidents of running backwards is quite unusual and Kubota didn't take this winching scenario into account.

QUOTE]

I just dug out the Kubota Work Shop Manual and checked. The DT, GST and HST all have a one way clutch in them to keep this from occuring.

He should call the dealer and bring it in to get it fixed before the engine is toasted.

jb

 

[ccsial]

John: That's interesting. Is the manual your looking in for the Grand L or the L4400 economy?

I know my L3400HST came with an ORC but they have eliminated that on the newer models because of some failures. I have the Kubota service bulletin that shows the new L3400 PTO clutch and the ORC feature is gone.

 

[L4400]

I had that happen several times with my old L2500. Had it happen driving it and bogged it and also had it happen running a post hole digger.

 

[SPYDERLK]

The L4400 has an independent PTO so it is not tied to the transmission. There is probably not an ORC since the PTO is tied directly to the engine. I suspect that the incidents of running backwards is quite unusual and Kubota didn't take this winching scenario into account.

QUOTE]

[[[I just dug out the Kubota Work Shop Manual and checked. The DT, GST and HST all have a one way clutch in them to keep this from occuring.]]]

He should call the dealer and bring it in to get it fixed before the engine is toasted.

jb

A one way clutch/ORC would not prevent this cuz they only prevent driving the engine in the forward direction.
larry

 

[rbargeron]

The L4400 has an independent PTO so it is not tied to the transmission. There is probably not an ORC since the PTO is tied directly to the engine. I suspect that the incidents of running backwards is quite unusual and Kubota didn't take this winching scenario into account.

QUOTE]

I just dug out the Kubota Work Shop Manual and checked. The DT, GST and HST all have a one way clutch in them to keep this from occuring.

He should call the dealer and bring it in to get it fixed before the engine is toasted.

jb

Hold on a minute here. The direction of the torque did not change - so an ORC wouldn't have any effect. The engine was trying to turn the winch, and the winch was resisting, slowing the engine rpm down more and more until it got to zero and then became negative. But during this the pto shaft torque did not switch direction - the orc remained positively loaded.

It's not unheard of for a winch to lift a tractor's front wheels off the ground, stalling the engine, and turning the engine backward as the front settles back down. If the engine actually fired and made power in the reverse direction, then the ORC would become unloaded and would disconnect.

 

[ccsial]

A one way clutch/ORC would not prevent this cuz they only prevent driving the engine in the forward direction.
larry

your right. I didn't think about that.

 

[dfkrug]

I suspect that all you would have to do to cause the engine to run
backwards is to stall it. You do not need to give it an external reverse
torque. That is because if one of the cyls is on its compression stroke
(likely!) there may be enough reverse torque created internally. It only
takes a partial reverse revolution for the engine to fire in the reverse
direction.