QUADRA-DRIVE II – SYSTEM STRUCTURE & FUNCTION

System Overview

The Quadra-Drive II system is Jeep’s premium full-time four-wheel drive platform, implemented on the Overland Summit trim for maximum torque vectoring and terrain response. It utilizes a combination of the NV245 transfer case and two electronically controlled limited-slip differentials (ELSD) to enable torque delivery to any single wheel with available traction.

• Front Axle: ELSD with gear-actuated clutch pack
• Rear Axle: 230MM ELSD with electronic torque bias control
• Transfer Case: NV245, full-time with low range
• Control Method: Terrain-specific electronic actuation via ABS and PCM

Operational Architecture

Quadra-Drive II responds in real-time to wheel speed differential, ABS data, and throttle position. When slippage is detected, torque is directed to wheels with grip by modulating ELSD clutch pack engagement. In extreme conditions, the system can deliver nearly 100% torque to a single rear wheel. Brake lock differential (BLD) logic supplements ELSD function by applying friction to spinning wheels to assist in torque redirection.

• Response Time: Millisecond-level slip detection
• Communication Bus: CAN-linked to PCM and ABS modules
• Input Signals: Throttle angle, wheel speed, brake pressure
• Logic Integration: Fully embedded in terrain response profiles

Maintenance Protocols

Both ELSD-equipped differentials use specialized limited-slip gear oil (Mopar Synthetic 75W-140) and must be serviced every 30,000–40,000 miles to retain clutch pack health. Differential fluid must be friction-modifier compatible, and off-brand oils may reduce effectiveness or trigger chatter. Drain plugs use a 14mm hex; rear diff uses 230MM ring gear architecture.

• Fluid Spec: Mopar Synthetic 75W-140 with LS additive
• Service Interval: 30,000–40,000 miles under moderate load
• Rear Axle: 230MM ELSD Dana variant
• Front Axle: Gear-actuated limited-slip, 195MM

Failure Modes & Diagnosis

The most common issues arise from neglected fluid, thermal overload, or control module faults. A failing ELSD may present as limited traction under load or clicking noises during turning. Module faults may produce "Service 4WD System" warnings and lock the drivetrain in default open diff behavior. Diagnosis requires access to ELSD data via advanced scan tool.

• Chatter in Turns: Low fluid or worn clutches
• Reduced Traction: ELSD in passive mode or disabled
• Error Message: TCCM or ABS bus fault
• Noise Under Load: Internal gear slippage or degraded pack

System Advantage & Application

Quadra-Drive II offers superior control in rock, snow, and uneven terrain. The ELSDs function independently of brake systems under most conditions, providing a more refined and less thermally aggressive solution compared to BLD-only configurations. This setup allows true torque delivery under throttle without full wheelspin interruption.