Part of the New Holland Repair Manuals.
Row unit gearbox timing and slip clutch settings on a 974 corn head are settled by factory literature and nothing else; this 86-page New Holland 974 service manual PDF, OEM number 40097412, is that literature. The gearbox chapters take up most of the book: input shaft and stalk roll drive teardown, gathering chain drive assembly for both Style 1 and Style 2 units, and the backlash checks that keep row unit timing honest. A labor guide and a full specifications chapter cover the auger, stalk rolls, deck plates, and weed knives, so you can plan the whole job before pulling a shield. Mic the sprocket bushing during inspection; past 3.010 in. (76.5 mm) inside diameter it gets replaced, and the auger slip clutch sets at 240 ft. lbs. (325 N-m). When a row unit quits at dusk, there is nobody to ask. Bookmarked and text-searchable, this PDF goes wherever your header sits.
What's Inside This Manual
| System | Pages | Key Topics |
|---|---|---|
| Safety | 3-6 | Safety Precautions |
| General Information | 7-8 | Serial Number Plate, Improvements, Hardware Information, Hardware Key |
| Auger Slip Clutch | 9-12 | Removal and Disassembly, Inspection |
| Row Unit Slip Clutch | 13-38 | Removal Style 1, Removal Style 2, Inspection, Disassembly, Assembly, Installation Style 1, Installation Style 2 |
| Stalk Rolls | 39-44 | Removal, Front Stalk Roll Bearing Removal, Stalk Roll Installation |
| Removal of Row Unit Gearbox | 45-46 | Removal, Crop Dividers, Braces, Drive Shields, Drive Chain |
| Initial Disassembly and Input Shaft | 47-49 | Service Tools, Gearbox Cover, Input Shaft Disassembly, Stalk Roll Drive Disassembly |
| Stalk Roll Drive and Bearing Removal | 50-51 | Roll Shaft Removal, Bearing Removal, Square Shaft Removal |
| Gathering Chain Drive Disassembly | 52-53 | Style 1 Disassembly, Lower Bearing Removal, Upper Bearing Removal |
| Inspection and Assembly Notes | 54-55 | Parts Layout, Inspection Procedures, Assembly Notes |
| Gearbox Assembly and Timing | 56-62 | Gathering Chain Drive Assembly, Input Shaft Assembly, Stalk Roll Drive Assembly, Backlash Check |
| Style 2 Gathering Chain Drive | 63-77 | Style 2 Parts Layout, Style 2 Assembly, Input Shaft End Play, Gear Backlash Adjustment |
| Final Assembly and Installation | 78-80 | Final Assembly, Installation, Labor Guide |
| Labor Guide | 81 | Auger Slip Clutch, Row Unit Slip Clutch, Row Unit Hex Drive Shaft, Stalk Row, Front Stalk Roll Bearings, Row Unit Gearbox, Input Shaft, Gathering Chain Drive |
| Specifications | 82-83 | Gathering Chain, Dividers, Deck Plates, Stalk Rolls, Weed Knives, Auger, Slip Clutches, Row Unit Drive |
Quick Reference Specifications
| Specification | Value | Page |
|---|---|---|
| Auger slip clutch torque | 240 ft. lbs. (325 N-m) | p. 10 |
| Maximum ID of the sprocket bushing | 3.010" (76.5 mm) | p. 10 |
| Torque for cap screws, D (Figure 3-4) | 66 ft. lbs. (90 N·m) | p. 42 |
| Torque for cap screws, B and C (Figure 3-10) | 15 ft. lbs. (20 N·m) | p. 43 |
| Input shaft bearing puller washer size | 1-1/4" OD x 3/16" thick (32 mm x 5 mm) | p. 49 |
| Stalk roll bearing installation pipe size | 2-5/8" OD x 8" long (67 mm x 203 mm) | p. 51 |
| Cap screws (stalk roll drive gear) | 66 ft. lbs. (90 N·m) | p. 73 |
| Gathering chain free movement | 1/4 inch (6 mm) | p. 75 |
| Row Unit Gearbox Grease Capacity | 5 lbs. | p. 78 |
| Input Shaft End Play | 0.001-0.031 inches | p. 75 |
| Stalk Roll Drive Gear Backlash | 0.015-0.025 inches | p. 75 |
| Gathering Chain Drive Gear Backlash | 0.015-0.025 inches | p. 75 |
