No Forward On A John Deere 310C After Rebuilding The Reverser

[MikePhua]

Background On The John Deere 310C
The John Deere 310C is a classic backhoe loader featuring a 65 hp (48.5 kW) 4239D four‑cylinder diesel engine and a full‑power‑shift reverser with multiple wet‑disk clutches.  It’s widely used in small construction, utility, and agricultural work. Over its production run, many operators have relied on its ruggedness, but its reverser transmission is also known to require careful maintenance and rebuilds.
The Problem: No Forward After Rebuild
A typical scenario: an owner acquires a 310C that hasn’t run in a while, then notices weak reverse and almost no forward drive. After removing the reverser, they order a full rebuild kit including the pump, and when disassembling they find the forward clutches are severely worn. They install all new friction plates, steels, seals, and bearings, flush all hydraulic lines and the cooler, then reassemble. However, once back together, the machine spins the tires in reverse but still refuses to pull forward. Disconnecting the clutch solenoid wiring doesn’t fix it.
Likely Culprit: Forward Clutch Pack Clearance
One experienced technician immediately suggests checking the forward pack clearance, and this is not guesswork: improper clearance within a clutch pack can prevent the forward clutch from engaging correctly, especially after a rebuild. If the clearance is too tight, the new friction plates may bind; if too loose, hydraulic pressure may not be adequate to clamp the pack under load.
Other Possible Causes
Beyond clutch clearance, several common issues on the 310C’s reverser system can lead to a “no forward” condition:

• Worn or damaged control valve: Even though the owner cleaned and inspected the control valve during rebuild, residual debris or internal wear may prevent correct hydraulic routing.
  
• Improper pump calibration: If the charge or pressure pump is not properly set, the system may build enough pressure for reverse (which often requires less) but fail under forward load.
  
• Incorrect fluid type or level: Using the wrong hydraulic/transmission fluid grade or neglecting correct fill procedure can lead to poor clutch apply pressure or air entrainment.
  
• Solenoid or wiring issue: Though the owner tried disconnecting the solenoid (which didn’t help), a weak solenoid, poor wiring, or intermittent electrical problem can still prevent full engagement.
  
• Torque converter or pump wear: Even with a rebuilt reverser, if the torque converter is worn or the pump support bushing (or pump drive) is out of spec, forward drive force may be compromised.
  

Diagnostic Steps
Here’s a structured approach to diagnose and fix the issue:

1. Re‑check forward clutch pack clearance
   • Remove the reverser cover if necessary.
     
   • Measure the clearance between the friction plates and steels according to Deere’s service specs. Adjust if out of tolerance.
     
2. Conduct pressure testing
   • Install a hydraulic pressure gauge on the test port for clutch apply pressure.
     
   • Compare measured pressure during forward engagement to manufacturer specification. If pressure is low, the cause may be internal leakage, worn pump, or incorrect pump preload.
     
3. Inspect the control valve again
   • Disassemble and inspect all spools for scoring, sticking, or wear.
     
   • Clean all passages and replace any o-rings or seals that look damaged or old.
     
4. Verify solenoid operation
   • Check voltage and continuity on the clutch solenoid coil.
     
   • Activate the solenoid manually (using a jumper) to confirm it functions and moves the valve.
     
5. Examine the torque converter and pump drive
   • If pressure testing is inconclusive, remove the reverser and inspect the torque converter.
     
   • Check the front bushing on the pump or support housing for wear; excessive clearance there can starve the system.
     
6. Bleed the system properly
   • After rebuild, ensure all air is removed from hydraulic and transmission lines. Trapped air can compress under load and reduce effective clutch force.
     

Maintenance Lessons And Tips

• When rebuilding a reverser, don’t neglect the finer details like clutch clearances — even small mistakes can render a rebuild ineffective.
  
• Use the correct hydraulic fluid. Old or incorrect fluid can damage new clutch components quickly.
  
• Plan to pressure-test after reassembly, not just rely on function check.
  
• Keep logs of each build: record clutch clearances, pressure test numbers, solenoid resistance, etc., so future diagnostics are easier.
  

Conclusion
A “no forward” issue on a John Deere 310C after a reverser rebuild is rarely simple: even with worn clutches replaced, if clearances, pressure, or the control valve are not correctly addressed, the machine may still only move in reverse. The key is to methodically verify clutch pack clearance, test hydraulic pressure under load, inspect solenoids and the control valve, and ensure all reassembly and bleeding steps were properly completed. With patience and the right technique, many backhoes can be returned to full forward and reverse function without repeated part swaps.