Description
Genuine Bendix OEM 065706 TP-3DC tractor protection valve with integrated double check valve, mounted behind the cab on FMVSS-121 tractor air-brake systems. The valve isolates the trailer service and supply lines from the tractor air system if a trailer breakaway, hose failure, or supply pressure drop occurs, automatically closing the trailer supply at 20 ± 5 psi to preserve tractor brake function. The integrated DC-style double check selects the higher of the primary and secondary brake-system pressures to feed the trailer service line.
Signs You Need a New Tractor Protection Valve
- Trailer service brakes apply or release sluggishly
- Trailer supply (red knob) will not stay charged or pops out under braking
- Continuous air loss with the trailer connected, no audible leak at the lines
- Stop-lamp switch port leaking or stop lamps not actuating
- Tractor system pressure drops when the trailer brakes are applied
- Failure to close at 20 ± 5 psi during a breakaway test
Specifications
| Manufacturer | Bendix |
|---|---|
| Part Number | 065706 |
| Part Type | TP-3DC Tractor Protection Valve, Integrated Double Check |
| Tractor Control Ports (Primary + Secondary) | 3/8″-18 NPT |
| Stop-Light Switch Port | 1/4″-18 NPT |
| Tractor Protection Port | 1/4″-18 NPT |
| Trailer Supply Port | 1/2″-14 NPT |
| Trailer Service Port | 1/2″-14 NPT |
| Service Line Shut-Off Pressure | 20 ± 5 psi |
| Mounting | 2 × 0.34″ mounting holes, behind-cab mount |
| Operating Temperature Range | -40°F to 200°F (-40°C to 93°C) |
Cross References
This valve replaces or is equivalent to the following part numbers:
- Bendix: 065706, 65706, BX065706, BW065706
- Mack: 745-065706, 21024860
- Newstar: S-16394
- Tectran: TV065706
- Torque Parts: TR065706
- Automann: 170.065706
- Fortpro: F224685
- PAI / FortPro alt: LPV-5237
- PTP: GN065706
- World American: WA65706
- Also known as: 109790, 109553, 5001455, 641398, ACA-49361700, BEN065706, 065706BXW
Applications
This TP-3DC valve is used on Class 8 highway tractors with dual-circuit FMVSS-121 air-brake systems pulling trailers, including:
- Freightliner, Kenworth, Peterbilt, Mack, Volvo, International on-highway tractors
- Day-cab and sleeper combinations using behind-cab tractor protection mounting
- Single and tandem-trailer pulling configurations
Verify port sizes and mounting pattern before installation. Replace any worn or damaged glad-hand seals at the same time to prevent recurring trailer supply leaks.
