TRANSMITTER ASSEM 3N7615 - Caterpillar

Charging with Oil (Original or refill after significant servicing)
This procedure is recommended if the suspensions have experienced a fluid loss due to some other reason than an external leak. If an external leak develops, the suspension should be removed and replaced.
Suspensions are delivered with the proper amount of oil and should not require checking when new or rebuilt.The oil level of the suspensions mounted on a truck may be checked and adjusted as follows:
During truck operation, the nitrogen precharge in the strut tends to mix with the oil. The mixture appears as an oily froth that comes out of the suspension when the nitrogen pressure is released. To measure the oil level, the nitrogen must be removed from the oil. The nitrogen is removed by drawing a vacuum on the gas portion of the suspension assembly or by supporting the frame adequately with blocking and opening and leaving open the upper charge valves for 24 hours. The only time that the nitrogen should be removed is if external leakage is evident (indicating the need for repair) or when the empty to loaded deflection seems excessive.
On trucks equipped with later versions of the suspension, a setscrew/drain plug combination is installed at the bottom to allow the easy draining of the oil if so desired. Always release all residual pressure in the system prior to beginning to drain the suspensions by any means. If the plugs are removed, the plugs should be reinstalled.
The procedure assumes that the suspensions are mounted on a truck.
Park the truck in a safe position and secure the truck by means other than the trucks friction brake system.
Raise the truck until the suspensions are fully extended. Secure in this position with suitable blocking. 1650 mm (64.9 inch).
Remove the protective covers over the charge valves and carefully open both valves, releasing the gas charge.
Connect a vacuum pump to one of the charge valve assemblies to allow a vacuum to be drawn.
Verify that the other charging valve is closed.
Start the vacuum process and monitor the progress until all gas has been extracted. All gas will be removed when the oil in the suspension turns a smoother, darker color.
Do not allow liquid oil to be drawn from the suspension.
Typically this process will take approximately 15 minutes (with a vacuum of 98 kPa (29 inch mercury)) to 30 minutes (with a vacuum of 34 kPa (10 inch mercury)).
Stop the vacuum process.
Remove the blocking and slowly lower the truck frame until the distance between the upper and lower mounting pins are approximately 1515 13 mm (60 0.5 inch).
Release any residual gas pressure in the suspension as outlined previously.
Remove the weigh system transducer port adapter fitting near the top of the suspension and replace with the appropriate charging adapter.
Open the port and observe if oil flows from the vent hole in the adapter. If not, the oil level is low and charging as outlined below is required.
Attach the oil charging kit to this port.
Connect the suction line of the charging