Specifications, Service and Repair of Farm and Lawn Tractors

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John Deere 3520 Tractor Specs Overview

John Deere 3520 Tractor Engine

Engine Model - Yanmar 3TNV84T
Cylinders - 3
Displacement, cu in (L) - 91.5 (1.496)
Engine Bore, in (mm) - 3.3 (84)
Engine Stroke, in (mm) - 3.54 (90)
Block Design, Replaceable Liners - Cast in block
Aspiration, Turbocharged or Naturally Aspirated - Turbocharged
Engine Power, Rated, hp (kW) - 37.2 (27.7)
Maximum Engine Power, hp (kW) - Same as Advertised
Engine Speed, rpm - 2600
Power Boost, hp (kW) - No boost
Fuel Tank, gal (L) - 13.5 (51.1)
Fuel System Description - Rotary-Distributor Type
Fuel System Control - Mechanical
Fuel Injection to combustion chamber - Direct
Exhaust Pipe - Underhood std; vertical opt
Fan Drive Type - Belt
System Rating, Volts - 12
Alternator Rating, Amps - 40

John Deere 3520 Tractor Transmission


Description - Power Reverser
Transmission Type - 3 Range, 4 Gear
Forward / Reverse Speeds - 12F / 12R
Maximum Speed Forward, mph (kph) - 16.4 (26.4)
Shuttle (Forward-Reverse) - Std

Optional Transmission


Description - eHydro
Transmission Type - 3 Range Hydrostatic
Forward / Reverse Speeds - Infinite, 3 range

John Deere 3520 Tractor PTO (Power take off)

PTO Horsepower, hp (kW) - 30.5 (22.7) / 30 (22.4)
PTO Speeds, rpm - 540
PTO operational Type - Independent

Wheels

Drive Wheels - 4WD
Tractor Steering Configuration - Front Steer

Rear Axle

Final Drive - Spur gear
Axle Output End - Flange
Axle Bar Diameter, in (mm) - No bar axle

Brakes

Brake Type - Wet disc

John Deere 3520 Tractor Hydraulic System

Hydraulic System Type - Open center
Standard Pump Flow, gpm (Lpm) - 13.9 (52.5)
Standard Remote Valves - 5

Tractor 3-Point Hitch Features

3-Point Hitch Category - Category 1
Draft Sensing or Lift Control - Position Control
Draft Link Ends Adjustable - Optional

3-Point Hitch Lift Capacity

Standard Lift Capacity 24 Inches behind pin, lb (kg) - 2,220 (999)

Drawbar

Drawbar Description - Adjustable length

Wheelbase

Wheelbase, 4WD, in (mm) - 68 (1727)

Tire Size


Front Tire Size, 4WD - 7.0-14 / 6PR R1
Rear Tire Size - 11.2-24 / 6PR / R1

JD 3520 Tractor Transmission

AutoHST:

- Familiar car-like control layout.

- Engine speed controlled with single pedal.

- Automotive Cruise, SpeedMatch and MotionMatch customize speed to any application.

- Shift lever on the console for forward, neutral and reverse.

- Available on the John Deere 3520 Tractor open station tractors eHydro.

Effortless two-pedal automatic transmission. With easy shifting from forward to reverse at the touch of a pedal, it’s ideal for everything from loading to mowing.

Automotive Cruise, SpeedMatch and MotionMatch customize speed to any application.

Plus, there’s a LoadMatch power management system.

PowrReverser - Convenient dash-mounted lever makes this manual transmission easy to shift from forward to reverse without clutching—a noticeable benefit when loading.

Service JD 3520 Tractor Engine

Adjusting Belt Tension:

- Loosen nut on tensioner sheave.

- Slide tensioner downward for more tension on belt or upward for less tension on belt.

- Tighten nut on tensioner sheave and check belt tension. Adjust as necessary.

- Lower hood.

Replacing Belt:

- Replace alternator belt if excessive wear, damage or stretching is detected.

- Raise hood.

- Disconnect black negative (-) cable from battery.

- Loosen nut on tensioner sheave.

- Slide tensioner upward to remove tension on belt.

- Remove belt from compressor sheave, engine sheave, and tensioner sheave.

- Install new belt over engine sheave and then onto remaining sheaves.

- Apply pressure to tensioner sheave until tension is correct and tighten nut.

- Check belt tension, and adjust as necessary.

- Connect black negative (-) cable to battery.

- Lower hood.

Testing JD 3520 Tractor Rear PTO Knob

- Push all PTO engagement knobs to the disengaged/off position.

- PowrReverser: Depress clutch pedal completely and move the transmission range and gear shift levers to the N (neutral) position.

- Move the Power take off selector lever to the rear PTO only position.

- Pull the rear PTO engagement knob to the engaged/on position.

- Turn key switch to start position. Engine must not crank.

- Push all PTO engagement knobs to the disengaged/off position.

- Turn key switch to off position.

Testing John Deere 3520 Tractor Rear PTO and Seat Switch Interface

- Push all Power take off engagement knobs to the disengaged/off position.

- PowrReverser: Depress clutch pedal completely and: Move the transmission range and gear shift levers into the N (neutral) position / Move the reverser lever to the center neutral position.

- Start engine.

- Move the Power take off selector lever to the rear PTO only position.

- PowrReverser: Release clutch pedal.

- Pull the rear PTO engagement knob to the engaged/on position.

- Raise up from operator’s seat. Do not dismount machine.

- Engine should stop.

- Push all PTO engagement knobs to the disengaged/off position.

- Turn key switch to off position.

Testing JD 3520 Tractor Rear PTO and Park Brake Interface

- Push all PTO engagement knobs to the disengaged/off position.

- PowrReverser: Depress clutch pedal completely and: Move the transmission range and gear shift levers into the center N (neutral) position / Move the reverser lever to the center neutral position.

- Start machine engine. Set engine speed at 1500 rpm.

- PowrReverser: Release clutch pedal.

- Raise up from operator’s seat. Do not dismount machine.

- Pull the rear PTO engagement knob to the engaged/on position. Rear PTO should operate.

- Rear PTO should operate.

- Unlock park brake.

- Engine should stop.

- Push all Power take off engagement knobs to the disengaged/off position.

- Turn key switch to off position.

Testing Reverse Implement Option (RIO)

- Start engine.

- Set engine speed to 1600 rpm or less.

- Engage PTO to start attachment.

- Set Power take off Selector Lever to Mid or Mid and Rear.

- Look behind and down before backing up to be sure there are no bystanders and there is a clear path.

- Begin reverse travel by depressing reverse travel pedal.

JD 3520 e-hydro, about 5 years old, 250 hours on it. I was clearing some brush yesterday and about 3 hours into it, as I started to back up it stopped like I had raised up off the seat and wouldn't move again. The dash showed Err 57. All the hydraulics work fine, even the rear PTO works fine. It just won't move at all. I assumed since I was clearing brush that a stick or something must've broke a wire or something but I can't find anything wrong. I have searched the internet for this issue and it seems that it could be anything from a weak battery to a fried computer board. I have checked the battery, its showing 12.52v. I've checked the jumper wire under the brake pedal area and it seems to be working ok. I'm assuming that the seat switch is fine because I can turn on the rear PTO and it will stay running until I raise off the seat. I have 4 fuses and they're all ok. Any troubleshooting help would be appreciated or if someone has a technical manual, that would be great.

I had one that had code 57. On that one the ground wire for the ehydro controller unit had a break in the harness. I never identified the break in the harness, but I spliced in a new ground wire to make it work. Since it was under warranty, we replaced the whole harness. Never had a problem after that. That was on a 4320, but it is the same setup. There are other possibilities for this code, but you might check that out first. Don't remember which wire on controller plug is ground. I purchased my used tractor about a month ago and the first day out after about two hours of bush hogging, it just stopped - no forward or reverse, error 57, and everything else worked. I called and talked with the dealer technician and he suggested checking the wiring harness, connectors, etc. No luck. The next morning, it ran fine - I finished mowing, put on the box blade and working on the road, and again after about two hours it stopped again. I was now convinced it was heat related and pointed to the controller board. The dealer hauled it back to the shop and after a day of troubleshooting they say they found a pinched wire near the fuse panel and controller board (they think it was pinched from the factory). They claim they have fixed it and will be returning it soon.

has anyone experienced or know a fix for no power to forward or reverse and no power to PTO, m/c was working fine one minute and when I restarted it wouldn't do the above although the 3pt hitch works and the front loader is ok. Error 06 appeared on the dash so I replaced the MFWD sensor, this hasn't fixed the problem, my next plan of attack is to replace oil and side suction filter, hoping this works as I'm running out of ideas. When the problem occurred there was no catastrophic noise ,smoke or anything that rang alarm bells, engine started fine like it always does it just refuses to move. The tractor is a 2004 and I'm not the original owner, yes the error code is still showing. It does have dual pumps that would explain why the loader and 3pt hitch work.

Have changed transmission oil and filter, no change in problem, I suspect it's an electrical problem, will have to wait for technical manual. Had this issue last night on a 3320, try pulling the forward/reverse levers back towards you and see if the fault clears.

I have a JD 3520, approx. 3 years old, very low hours, sometimes when I push the pedals for forward or reverse, the speed of the tractor is just not there, in other words when it is acting up, I can floor the pedal and the tractor moves very slow. The problem seems erratic, temp doesn't seem to matter, and I check the fluid in the back. Sometimes if I rev the engine once or so, and then return speed down again it seems to clear it up, it’s like the oil pressure for the drive drops low sometimes. Rear and front lifts all work perfect, this is strictly like a transmission issue. Has anyone heard of this, or know what I can check.

Mine did the same try this. Look on the dash right side of the tach and you will have a rocker switch flip it and look under the tach for it to say loader off. If you have it switched to loader on it will do strange things.

My new 3720 started leaking fluid out the right front wheel seal this winter. Only did it when I brought it in a friends shop over night to thaw out and change oil. When I checked the fluid level found out it had pressure in the front diff. That’s when I called the dealer and found out it does NOT have a diff vent. How is that supposed to not blow oil out the seals? Any one else have this problem? Any vent mods? Dealer replaced seal on warranty but not convinced it won’t happen again without a vent.

I have a 2006 3520 and found the same thing. The only fix is to clean the fill plug area, and loosen the dip stick and leave this open until you are ready to use the machine again. I place a clean rag over all of this to keep dirt out of my axle, and put a note on my dash to remind me to tighten the fill plug back up. This stopped my axle from leaking. I found out when my axle started leaking on my front tire. I do not know what JD was thinking when they did this. I have not come up with any thing to vent the axle, because JD used some odd thread on the fill plug. I thought this was fix on the new machines by now.

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