A direct OEM-spec replacement inner arm for Lippert rack-and-pinion slide-out systems. Arrives with the gear rack already installed and a durable black powdercoat finish, so you can get your slide room moving again without sourcing separate rack hardware.
Lippert's rack-and-pinion slide-out mechanism relies on precision-machined steel arms that telescope in and out as the room travels. The inner (inboard) arm is the tube that rides inside the outer arm assembly and carries the gear rack that meshes with the drive gear on the motor unit. When teeth strip, the arm bends, or the powdercoat wears through and corrosion sets in, the whole slide system loses reliable engagement -- resulting in rooms that won't fully extend, bind mid-travel, or refuse to retract.
Part number 143710 is the Lippert-sourced replacement for that inner arm. It matches the 2.5 x 2.5 inch square tubing cross-section and the 15-tooth (new style) drive gear setup at 4 teeth per inch. At 70 inches in length, it fits the slide room depths these systems were originally engineered for. The gear rack comes pre-installed from the factory, saving installation time and ensuring the rack is properly positioned and secured.
Rack arrives already mounted on the arm -- no separate alignment or fastening of rack hardware required during your repair.
Spec matches the 15-tooth new-style Lippert drive gear. Ensures proper mesh and load transfer through the full travel cycle.
Corrosion-resistant finish protects the steel tubing from moisture and road debris under the RV chassis.
Sourced from Lippert to original engineering dimensions -- not an aftermarket approximation.
Lippert rack-and-pinion slide systems use a telescoping two-arm assembly per slide room corner. The outer arm is the fixed channel anchored to the RV frame. The inner arm (this part) slides within the outer arm and is attached to the slide room itself. The gear rack on the inner arm engages the drive gear turned by the slide motor, converting motor rotation into linear room movement.
When ordering a replacement, confirm you need the inboard inner arm -- meaning the arm positioned toward the centerline of the RV -- versus an outboard arm. Arm position, tubing size, length, and tooth pitch must all match to restore proper function.
Before purchasing, confirm all of the following on your existing slide system:
Replacing an inner slide arm is a hands-on repair that typically involves retracting the slide room, supporting the room's weight independently, unbolting the arm attachment points at the room and at the outer arm guide, withdrawing the old inner arm, and sliding the new arm into position. Because slide room weight and alignment are involved, two people are recommended for this repair.