International Harvester 3688
Production ended · 2WD or 4WD
PTO power · claimed
113 hp
- Weight
- 13,200 lb
- Engines
- 1 Diesel
- Built
- 2,572
- Price new · 1981
- $45,000
Power
| Engine | no record |
|---|---|
| PTO | 113 hp claimed |
| PTO, tested | 113.7 hp |
| Drawbar | 100.2 hp claimed |
| Drawbar, tested | 99.2 hp |
| Listed power | 125 hp PTO basis |
Engines
| International Harvester 7.1L 6-cyl dieselDiesel · 6 cyl | 436 ci |
|---|
Engine details
- International Harvester 7.1L 6-cyl diesel
- Bore × stroke
- 4.3 in × 5 in
- Rated speed
- 2,400 rpm
- Compression
- 16:1
- Cooling
- liquid-cooled
Transmissions
| 16-speed partial power shiftpartial power shift | 16F / 8R |
|---|
Transmission notes
16-speed partial power shift: Left lever selects gear, right lever selects high, low, or reverse range. Tractor may be shifted on the move without the clutch between gear pairs (1-2, 3-4, etc). Synchronized shifting, using the clutch, between gear pairs (2 to 3, 4 to 5, etc). The transmission is four-gear with the powershift provided by an electric solenoid actuated Torque Amplifier.
Weight
| Weight | 13,200 lb operating |
|---|---|
| Shipping | 11,300 lb |
Dimensions
| Wheelbase | 105 in |
|---|---|
| Length | 184 in |
| Width | 102 in |
| Ground clearance | 13 in |
| Front tread, narrowest | 60 in |
| Front tread, widest | 84 in |
| Rear tread, narrowest | 66 in |
| Rear tread, widest | 128.5 in |
Capacities
| Fuel tank | 50 gal |
|---|---|
| Hydraulic system | 22.5 gal |
Hydraulics
| System | closed center |
|---|---|
| Pump flow | 18 gpm |
| Total flow | 27 gpm |
| Steering flow | 12 gpm |
| Remote valves | 2 to 4 |
Hitch
| Rear hitch category | II |
|---|---|
| Control | draft sensing |
| Rear lift capacity | no record |
PTO
| Rear PTO | independent |
|---|---|
| Rear PTO speeds | 540/1000 (1.375) |
| Engine rpm at PTO speed | 540@2100 |
Chassis
| Drive | 2WD/4WD |
|---|---|
| Steering | Power steering |
| Brakes | Hydraulic wet disc brakes |
| Differential lock | rear |
| Final drives | bull gear |
| Cab | Cab standard with heat and air-conditioning. Optional burgundy or western finish interiors |
Tires
| Front | 11L-15 |
|---|---|
| Rear | 18.4-34 |
Electrical
| System voltage | 12 V |
|---|---|
| Ground | negative |
Production
| Total built | 2,572 |
|---|---|
| Price new | $45,000 (1981) |
| Factories | Rock Island, Illinois, USA |
| Built by | International Harvester |
Variants
- 3688 Hi-Clear high-clearance model
Serial numbers
Serial number plate on the right side of the tractor frame, ahead of the rear axle.
| Year | First serial |
|---|---|
| 1981 | 501 |
| 1982 | 1743 |
| 1983 | 2482 |
| 1984 | 2695 |
| 1985 | 3068 |
Literature
- Buyer's Guide 1982 International Harvester
- International 30 Series Tractors International Harvester
- Operator's Manual 3088, 3288, 3488-Hydro and 3688 Tractors (1258513C1) 1981
- Tractors 90 & 110 HP International Harvester, 1981
- 3288 and 3688 Product Guide International Harvester, 1981