3520 AutoHST No reverse - everything else works - 2008 140 hours

[cartel]

we rarely use this tractor as its only mainly used for field mowing- parked inside last winter and worked fine- went to start last week and dead battery- charged battery on ctek and it started up next day- let it run 10 min and shut off-- went out yesterday to move it and it wont go reverse. moves forward- in all gears .

loader works- pto works- 4-1 front loader bucket works- every other thing seems to work- i towed it out of the shop last night and it drives around forward fine- first time out i got a error code 06- i re-re the plug on the mfwd? switch and the codes now gone- the code didnt come on till i drove around. but after resetting the plug its still off.


how do i find / check the reverse prop valve wiring- i dont have a service manual as nothing has broken till now.

i have pulled the steering wheel off and tested the D_N_R switch with ohmmeter and both F and R get continuity on a terminal-
i then tested the switch with a test light and back probes and get voltage out of switch on separate terminals when moving switch to F and R so it appears the switch is fine- i havent checked actual voltage but the test light illuminates.

all i can think of next is to check the wiring to the reverse prop valve- if thats good i then guess its off to the dealer--

where is reverse valve located to test the wiring?


_______________________

saw this thread but its ehydro and i dont have a separate reverse pedal to test


http://www.tractorbynet.com/forums/...ating/342356-3x20-3520-ehydro-problem-no.html


Cocre posted this:
Default Re: 3x20 3520 eHydro Problem No Reverse No Error Codes Forward works Fine Please Help
I highly recommend that you buy the technical manual. It is easily worth the cost, even if you use it for nothing else but to better understand the operation of the machine. It is a work of art.

It appears to me that to get to the proportional and relief valves the tractor has to be split.

There are pressure test ports on the right side of the clutch housing. The right hand brake bellcrank has to be removed to get to them. Top port is forward, bottom port is reverse.

From the 3x20 technical manual.

Symptom: Machine Will Not Move in Reverse
Problem Cause - Solution
1. Machine moves in Forward only.
a. HST Check reverse pedal position sensor for calibration or malfunction. Repair or replace sensor.
b. Auto HST Check D-N-R switch and wiring to forward and reverse proportioning valves.
c. See Symptom: Machine Will Not Move In Forward or Reverse above.
2. Reverse proportional valve malfunctioning.
a. Replace valve.
3. Directional relief valve stuck open.
a. See Hydrostatic High Pressure Relief Test on page 661.
b. Replace relief valve.

 

[jeff9366]

Often this is one wire pulled of the reverse solenoid of the HST. Crawl under the tractor and look for a disconnected wire.

 

[beenthere]

:welcome: to TBN

I'd start with removing the neg cable to battery and let set for 20-30 minutes. See if re-setting the computer (whatever that might be) will bring you up from scratch. And if the battery is more than 6 years old, I'd replace it too..

Then I'd be sure to have the service tech manual by my side to poke around chasing a failure, in hopes to avoid dropping the tractor off at the dealer for them to poke and chase.

Wish you well in tracking this down.

 

[cartel]

it is the original battery- i did see a thread somewhere about clearing it - i will try that but with everything else working i doubt thats it.

the one wire falling off makes more sense- where should i be looking ..

i was underneath and didnt see any obvious hanging wire but no idea where to look

 

[jd110]

The first thing that comes to mind when something doesn't work after storage is possibility of mice or some other critter chewing through a wire somewhere. I would check for continuity in the orange #523 wire between the FNR switch and the drive controller. It goes to pin #E3 on the controller(computer) That is the wire that sends voltage from the switch in reverse to the controller.

 

[jeff9366]

i was underneath and didnt see any obvious hanging wire but no idea where to look.

On Kubotas it is underneath the tractor, below where your right foot sits on the floorboard when not on the throttle pedal.

 

[cartel]

jd110 -- where is the drive controller -

is there a schematic of that so i can locate it

thanks