Concise ordered procedure with the theory behind each action. I cover the two common “shift interlock” failures on an MF35: the clutch/neutral safety interlock (prevents starting or shifting unless clutch/neutral conditions are met) and the gearbox selector interlock/detent (prevents selecting two gears or accidental shift into gear). Steps show diagnosis, repair actions and exactly why each action fixes the fault.

1) Quick system overview (theory)
- Clutch/neutral safety: a mechanical or electrical switch tied to the clutch pedal or neutral slider ensures either the clutch is depressed or the transmission is in neutral before starting or before certain shift operations. Function is geometry or switch continuity: pedal movement changes switch state.
- Gearbox selector interlock/detent: internal selector forks, a selector cross-shaft or sliding collars and a small interlock pawl/spring arrangement force only one selector to engage at a time and hold selection until intended. Function is positive engagement geometry and spring preload to prevent simultaneous engagement or accidental shifts.

2) Symptoms → what to check first (theory)
- Symptom A (starting only in gear / no neutral safety): check clutch pedal freeplay, switch or neutral slider linkage; slack allows switch not to actuate.
- Symptom B (can shift into gear accidentally or two gears partially engaged / grinding): indicates worn/weak interlock pawl or bent selector rods or excessive play in forks — geometry no longer enforces exclusive engagement.

3) Safety and preparation
- Remove battery earth, raise and support tractor, drain gearbox oil if you must open the top cover. Theory: isolating battery prevents accidental start; draining reduces contamination when opening.

4) External linkage inspection and adjustment (clutch/neutral safety) — action + why it fixes
- Inspect clutch pedal pivot, clevis, pushrod, return spring and split pins for wear or excessive freeplay. Measure pedal freeplay to spec (or minimal freeplay).
- Theory: excess freeplay means the switch or linkage never reaches its actuated position; correcting freeplay restores the required travel so the safety switch sees the correct state.
- Adjust clevis length or pedal stop to restore specified freeplay; lubricate pivot.
- If there’s an electrical clutch switch, verify continuity when pedal depressed; replace if intermittent/corroded. Theory: replacing a failed switch restores reliable electrical path.

5) Neutral/selector external linkage check (if tractor uses a neutral slider)
- Move gear lever to neutral; inspect neutral slider linkage and return spring. Ensure neutral detent works and slider reaches neutral position fully. Tighten or replace worn clevis/pins.
- Theory: if neutral slider does not sit fully, the neutral safety won’t register and may allow shifting path errors.

6) Access gearbox top/interlock components
- Remove gearbox top cover or inspection plate to expose selector forks, cross-shaft, interlock pawl(s), detent balls/springs. Keep parts organized.
- Theory: interlock elements are internal; direct inspection reveals wear, broken springs, or missing detents.

7) Inspect selector interlock parts
- Look for broken/weak interlock springs, worn pawls, elongated holes in forks or selector shafts, rounded notches on collars, excessive side play on forks, and missing detent balls/springs.
- Theory: the interlock relies on firm engagement surfaces and spring preload. Wear reduces positive engagement, allowing two collars to partially engage or slip out of gear.

8) Measure and compare wear
- Visually compare pawl tips and notches; feel for play in selector shafts. If pawl tip radius is rounded or notch depth is reduced, the engagement angle is altered and will not hold securely.
- Theory: geometry change reduces mechanical advantage and spring force effectiveness; replacement restores original geometry and force.

9) Replace or rebuild worn parts
- Replace interlock pawl, springs, detent balls/springs, selector collars or forks if out of spec. Use OEM or correctly hardened parts.
- Theory: new parts restore spring preload, notch geometry and contact materials so the pawl positively engages the selector collar and holds it until an intentional shift moves it.

10) Re-establish shaft/fork alignment and clearances
- Refit forks and collars, ensure correct positioning of selector cross-shaft and that rotating selector shaft is timed with gear lever positions. Replace worn bushes or fit shims if shafts have excessive radial or axial play.
- Theory: restoring alignment prevents binding and ensures the pawl contacts the collar at the designed point; eliminates slop that allowed accidental shifts.

11) Reassemble and set external adjustments
- Reinstall cover, refill gearbox oil, reconnect linkage. Adjust clutch freeplay and pedal travel again if disassembled. Ensure neutral detent is positive at gear lever.
- Theory: correct oil and lubrication ensure smooth fork movement; readjustment after assembly ensures external geometry matches internal positions so safety switches and levers operate in the intended range.

12) Functional testing and verification
- With engine immobilized or battery connected per safety, verify: clutch switch continuity when pedal depressed, neutral switch continuity in neutral, gear engagement feels positive and only one gear engages, no grinding when selecting gears with clutch depressed.
- Theory: tests prove the control chain (pedal → linkage → internal interlock → gear selection) is restored and that the interlock physically prevents unsafe states.

13) How each repair action fixes the fault (summary)
- Tightening/adjusting external linkage fixes slack so switches and levers reach their designed positions; that restores reliable actuation of neutral/clutch switches.
- Replacing worn pawls/springs restores spring preload and correct engagement geometry so only one selector engages and it is held securely; this prevents partial engagements and accidental shifts.
- Replacing worn forks/bushes and correcting shaft play returns the correct positional relationship between lever and internal selectors, preventing misalignment failures.
- Lubrication and correct oil level allow smooth, repeatable motion so the interlock components seat properly rather than sticking or dragging.

14) Typical failure causes to prevent recurrence
- Neglect (wear and corrosion), lack of lubrication, bent linkages from misuse, broken springs from metal fatigue, and using wrong parts. Regular inspection and timely replacement of pawl/springs prevents re-failure.

Done.
rteeqp73

#massy Ferguson 1035( 1988 )model full ,repaired, denting. painting, &modified # full video

Westerasmaskiner Aktiv TH finger bar mower and Massey Ferguson 35 Working walk around of Westerasmaskiner Aktiv TH finger / sickle bar mower powered by my Massey Ferguson 35. Getting it ...

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