Mack 38QC4135M6 Steering Pump PAI 37390CROSS REFERENCE: 38QC4135M6 APPLICATION: Mack Multiple Use Application. DETAILS: 11 Gear Teeth 0. 75 in x 0. 63 in Length Gear Diameter (1) 3 4 in 14 in NPT Port (1) 3 4 14 O Ring Port BRAND: PAI 37390 Mack 38QC4135M6 Steering Pump PAI 37390. Diesel parts and commercial parts. Supports hydraulic pressure and maintains stable steering function in heavy duty use. All components are proudly manufactured in the U. S. A. by PAI Industries Inc., an ISO9001