Isn't this interesting?
Found a pull lever under the driver's seat and decided to check it out and see what it does. Low and behold it is the control cable for a very expensive Remco Driveshaft Release System (Over $1,500 New) that is typically used by folks who want to flat tow a vehicle 2WD or 4WD that requires the rear driveshaft to be unhooked so as not to burn up the transmission when flat towing due to lack of transmission lubrication when the vehicle engine is not running.
At one time somebody had some money that owned this truck.
Drive Shaft Disconnect Overview
When you tow your rear-wheel drive car, van, pickup or SUV, the drive shaft to the rear axle must be disconnected to prevent damage to the automatic transmission. This requires mechanical service under the car which is not convenient for RV towing. The Superior Driveline Drive Shaft Disconnect (DSC) was developed to provide a quick and easy way to disconnect the transmission while sitting in the driver’s seat. The disconnect (mechanical clutch) is installed into the rear portion of the vehicle’s drive shaft, near the rear axle. When disconnected, the rear axle is free to turn without turning the drive shaft or transmission. The drive shaft has a control cable attached to it which extends to a location under the driver’s seat. This control cable is pulled out to disengage for tow mode and pushed in to engage drive mode.
The Superior Driveline DSC allows RV’ers to tow their rear-wheel and four-wheel drive automatic transmission vehicles behind their motor homes with all four wheels on the ground – worry free. With the DSC there is no mileage accumulation on cable-driven speedometers. It disengages the drive train in ’tow mode‘ and the vehicle is towed with the transmission in Park. This means there is no rotational movement in the transmission, no wear and tear to the transmission components and the speedometer drive gears are not turning. Modern electronic speedometers have now replaced the cable-driven units so mileage accumulation is generally no longer an issue. The Superior Driveline DSC saves valuable time and money by eliminating the need for a trailer or dolly and making the transition from tow mode to drive mode in minutes.