NISSAN RE4R01A-HD PARTS INTERCHANGEABILITY CHANGE: REASON: PARTS AFFECTED:               (1)               (2)               (3)               (4)               (5)               (6)               (7)               (8)               (9)             (10)             (11)             (12) At the start of production for the 2001 model year the RE4R01A underwent significant changes in many of the internal parts which include the pump and converter as well as many of the drive and driven components. These changes were implemented in order to create a “heavy duty” version of this transmission to accommodate the more powerful 3.5 Liter engine that the Nissan Pathfinder and Infiniti QX4 were to receive. The Light Duty Low/Reverse Clutch Piston is .965” tall and uses individual return springs and retainer. The Heavy Duty Low/Reverse Piston is .709” tall and uses a return spring assembly. The Light Duty Forward Drum has a 3.78” opening for the sprag which is a 34 element unit (Refer to Figure 1) and the low/reverse clutch lug area is1.77” tall. The Heavy Duty Forward Drum has a 3.86” diameter opening for the sprag which is a 30 element unit and the low/reverse clutch lug area is1.65” tall. The Light Duty Overrun Sprag Outer Race is stamped and has an overall height of 2.382” The Heavy Duty Overrun Sprag Outer Race is cast and has an overall height of 2.47” The Light Duty Rear Planet is a Four (4) Pinion  design, (Refer to Figure 2). The Heavy Duty Rear Planet is a Five (5) Pinion design, (Refer to Figure 2). The Light Duty Front Planet is a Three (3) Pinion design and the pinions are riveted. The Heavy Duty Front Planet is a Four (4) Pinion design and the pinions are held in by screws, (Refer to Figure 3). The Light Duty High Clutch Drum is stamped and is 2.030” in overall height. It will accept up to Four (4) Friction Plates. The Reverse Input Clutch Hub at the bottom of the drum is 5.295” in diameter, (Refer to Figure 5). The Heavy Duty High Clutch Drum is a thicker stamping and is 2.505” in overall height. It will accept up to Five (5) Friction Plates. The Reverse Input Clutch Hub at the bottom of the drum is 5.017” in diameter, Refer to Figure 5). The Reverse Input Friction Plates for the Light Duty and Heavy Duty both have 30 teeth. However, the Light Duty Friction Plates have a LARGER inside diameter then the Heavy duty Friction Plates have. The Light Duty Reverse Input Drum is stamped and is 2.559” in overall height. The drum has Eight (8) Lugs in order to accommodate the Eight (8) Lug Front Sun Gear. The Heavy Duty Reverse Input Drum is cast and is 3.011” in overall height. The drum has Twelve Lugs in order to accommodate the Twelve (12) Lug Front Sun Gear, (Refer to Figure 6). The light Duty 2-4 Band is 2.250” wide, (Refer to Figure 7). The Heavy Duty Band is approximately 2.750” wide, (Refer to Figure 8). A number of the Internal Bearings have changed from the closed one piece design to the open two piece design.                                                                                                                                                                                                                                 The Light Duty High Clutch Hub is .875” in overall height, (Refer to Figure 4). The Heavy Duty High  Clutch Hub is 1.133” in overall height, (Refer to Figure 4). The Light Duty Front Sun Gear is an  Eight (8) Lug design. The Heavy Duty Front Sun Gear is a Twelve (12) Lug design, (Refer to Figure 6). Copyright © 2004 ATSG " 2 0 0 5 "  S E M I N A R  I N F O R M A T I O N Automatic Transmission Service Group SLIDE 5