Fast Gearbox 12JS160T/16JS200T Main Shaft Dual-Valve Air Line 666258-3 02001500066949
Product Functions
1. Airflow "Highway": This dual-valve air line serves as a critical link connecting the transmission shift lever assembly (follower valve/check valve), the dual-H valve, and the high/low range shift cylinder.
2. Precision Shifting: When you toggle the high/low range switch (or shift into the auxiliary gearbox range position) inside the cab, air pressure is rapidly transmitted through this line to the shift cylinder; this actuates the synchronizer, instantly switching between the "high range" and "low range."
Common Symptoms of Failure
1. Hissing air leak: A distinct hissing sound of air escaping can be heard from beneath the transmission when the vehicle is stationary or idling.
2. Inability to switch between high and low ranges: The truck may be stuck in either low range (unable to shift to high) or high range (unable to shift to low), resulting in limited top speed or a lack of power when climbing hills.
3. Delayed shifting or gear grinding: Insufficient air pressure prevents the auxiliary gearbox synchronizer from fully engaging; shifting is not only sluggish but often accompanied by loud, harsh grinding noises, which can easily damage the internal gears of the transmission.
FAST Gearbox Pneumatic System Repair & Replacement BOM List
| No. | Part Number / Code | Official Part Name (Standard) | Common Description / Function | Suggested Qty | Component Attribute |
|---|---|---|---|---|---|
| 1 | 666258-3 | Auxiliary Box Double-Valve Air Pipe Assembly | Hi-Low Range Double-Valve Air Line (Core Part) · The exact item you queried, including primary and secondary range shift nylon tubes. |
1 Set | Core Replacement (Mandatory) |
| 2 | F99660 or F96191 (Subject to gearbox model) |
Double H Valve Assembly | Hi-Low Range Control Valve / Double H Valve · The core control air valve. If air lines leak severely, it usually indicates wear or blow-by inside the H-valve spool; simultaneous replacement is highly recommended. |
1 Pcs | Highly Recommended |
| 3 | A-5000 or F96161 | Air Filter Regulator Assembly | Air Filter & Pressure Regulator Valve (2-in-1) · Filters and reduces pressure from the vehicle's air brake system before supplying it to the gearbox. If it fails, oil/water will corrode new lines quickly. |
1 Pcs | Highly Recommended |
| 4 | 12JS160T-1707060 (Varies by speed/torque) |
Hi-Low Range Cylinder O-Ring Repair Kit | Auxiliary Cylinder Seal Kit · Includes O-rings and seals for the auxiliary cylinder piston. Recommended for maintenance during air line replacement to prevent internal "air blow-by." |
1 Set | Optional Maintenance Part |
| 5 | Matched by specific sizes (e.g., Q2540808, etc.) |
Push-in Swivel Elbow / Straight Fitting | Air Tube Fitting Kit · Copper/nickel-plated push-to-connect fittings. Internal plastic locks and rubber rings age quickly; reusing them will cause leaks. Must be replaced with the new tube. |
1 Pack (Approx. 2-4 pcs) |
Mandatory Pair (Replace with tube) |
| 6 | General Hardware Standard | High-Temp Nylon Cable Ties / Anti-Abrasion Corrugated Sleeve | Consumables (Anti-Chafing Protection) · Used for securing and bundling new air lines, wrapped with corrugated sleeves to prevent metal-to-plastic friction against the chassis or gearbox casing. |
As Needed | Essential Accessories |
DETAILS
| DESCRIPTION | Main Shaft Dual-Valve Air Line | PART NUMBER | 666258-3 02001500066949 |
| WEIGHT | 1kg | VOLUME | 30cm × 25cm × 5cm |
| TRUCK MOLDE | FAST | QUALITY | Copy,High Copy, OEM,Original |
| MOQ | 1 | WARRANTY | 1 year |
| PAYMENT | TT/WESTEN UNION | SHIPMENT | by air/sea/railway |
| BRAND | SINOSACHS | PLACE OF ORIGIN | JINAN CITY,CHINA |
| STOCK | IN STOCK | APPLICABLE SITE | GEARBOX |
| PACKAGE | Carton/Woodenbox | PORT OF LANDING | Qingdao Port,China |
