6T40 automatic transmission oil pump assembly hub stator

Top Failure Modes:

1. Stator Shaft Galling/Scoring – Poor lubrication or debris causes wear on the stator support hub, leading to pressure loss.

2. Bushing Wear – The pump bushing wears, causing rotor misalignment and low line pressure.

3. Seal Ring Groove Damage – Worn grooves allow internal leaks, reducing pump efficiency.

4. Cracking Near Drive Lugs – Fatigue fractures from high torque loads (common in 6T40s).

5. Stator Shaft Spline Wear – Slippage or stripping due to excessive torque or misalignment.

Key Symptoms:

• Low line pressure (delayed shifts, slippage)

• Whining noise (pump cavitation)

• Metal debris in fluid (bushing/seal failure)

Fix: Replace the pump assembly (including bushings/seals) and flush the system.