Stellar Automotive Group 4L40E/5L40E Overdrive Clutch Molded Piston fits GM

Stellar Automotive Group 4L40E/5L40E Overdrive Clutch Molded Piston (RWD, excludes AWD) – Compatible for GM & BMW 2000-2010

Stop slipping in 4th-5th gears, delayed upshifts, and burnt overdrive clutches with this upgraded molded overdrive clutch piston from Stellar Automotive Group.

This direct-replacement piston is the critical apply component for the overdrive clutch pack in all 4L40E and 5L40E transmissions (RWD applications only – excludes AWD models). The factory piston commonly cracks or loses its bond under heat and mileage, causing internal leakage that weakens overdrive apply — leading to flare on upshifts, slipping under load, and rapid clutch failure. This molded piston with permanently bonded rubber seal restores full line pressure, delivers crisp 4th-to-5th transitions, and protects your overdrive clutch pack for reliable daily driving or light towing.

Perfect fit for popular RWD models including:

• Chevrolet Trailblazer, SSR
• BMW 3 Series (E46), 5 Series (E39)
• Cadillac CTS (early), Escalade (select RWD)

Symptoms of a failing overdrive piston:

• Flare or slip on 4-5 upshift
• Delayed engagement in overdrive
• Harsh shifts when overdrive finally grabs
• Burnt overdrive frictions on teardown

Don’t let a $50 piston destroy a $500 clutch pack — install the Stellar Automotive Group molded overdrive piston and shift strong through every gear.

Note: All parts are distributed, not designed or manufactured, by Stellar Automotive Group.

Add this essential 4L40E/5L40E rebuild part to your cart today and enjoy crisp, reliable shifts!