JD 110 Tractor Loader Backhoe bucking motion

[jimbode]

Problem with my 2004 Model 110 TLB.
With either forward or reverse pedal pressed it abruptly alternates between desired speed and zero speed at a cycle of about once per second but not even spaced. This creates a strong bucking motion. The manual Inching Control operates fine with smooth controlled forward or reverse at all speeds. I believe there is much in common between foot pedal operation and the Inching operation such as sensors. Also the power to the foot pedal potentiometers and inching potentiometer is common. The HST proportional solenoids are common and work fine with Inching.

I suspect the HST controller but still not sure if there is a sensor used in foot pedal operation that is ignored in Inching operation. For example those related to engine load balancing. If so that sensor might be the problem.

No error codes are displayed. I think that means sensors and controls attached to the HST controller are probably OK. I tested error code display by press of both F and R pedals together and correct code is displayed.

Are there any other tests/experiments I can do before biting the bullet and ordering a new HST controller. ($712)

 

[TractorTech]

It sounds like the speed sensor mounted on top of the bell housing has gone bad. It's also only about $80.
I had one that did the same thing, intermittently. Replaced sensor, then great. And yes, no codes.
LVA11184 is the part number.

 

[jimbode]

Thanks Tractor Tech. I have the sensor on order. New Part # for LVA11184 is JDLVA17409. I hope that's it. Will post results.

 

[GreatWhitehunter]

Common problem frequently discussed, see thread:
http://www.tractorbynet.com/forums/...ing/333066-john-deere-110-loader-backhoe.html
You can also unplug the sensor and see it the problem goes away, you will get an error code when unplugged.

Matt

 

[jimbode]

Thanks Matt. I did as you suggested and unplugged. Yep, error code . _ _ . as expected and almost normal operation. Engine Speed Sensor scheduled to ship on 25th so OK the way it is until I get it replaced.
Maybe this solves another old problem too. Before I got a trailer I had a 5 mi trip to make. In High range and near max RPM I'd notice that it seemed to be downshifting some even on down hills. Then last year a couple of times it surged and I replaced the filters (overdue) and seemed ok. Then this year intermittant until warm and this week it became unusable. I'll post an update when sensor is replaced.