Page 1 of 8 2005 Chevrolet Chevy Express 6.0L Eng G2500 4L80E, MT1 AND 4L85E, MN8 SIMPLIFIED VALVE BODY RECONDITIONING INSTRUCTIONS, DTC P0741, P0742, P0751, P0752, P0756, P0757, P0894, HARSH OR DELAYED SHIFTS, SLIPS, NO DRIVE, NO REVERSE TECHNICAL SERVICE BULLETIN Reference Number(s): 08-07-30-001, Date of Issue: January 16, 2008 1997-2000 Chevrolet Silverado; 1997-2002 Chevrolet Silverado Chassis Cab; 1997-2003 Chevrolet Express; 1997-2006 Chevrolet Suburban; 1997-2008 Chevrolet Express Panel, Cutaway Vans; 2001-2006 Chevrolet Silverado 2500 HD, Silverado 3500 HD; 2002-2006 Chevrolet Avalanche; 2004-2006 Chevrolet Express 2500 HD, Express 3500 HD; 2004-2008 Chevrolet W3500/4500 Series Medium Duty Tilt Cab Models; 1997- Affected 2003 GMC Savana; 1997-2008 GMC Savana Panel, Cutaway Vans; 2001-2002 GMC Model Classic Sierra 3500 HD Chassis Cab; 2001-2006 GMC Sierra 2500 HD, Sierra 3500 (s): HD; 2001-2007 GMC Yukon XL; 2002 GMC Sierra Chassis Cab; 2004-2006 GMC Savana 2500 HD, Savana 3500 HD; 2004-2008 GMC W3500/4500 Series Medium Duty Tilt Cab Models; 2006 GMC Yukon Denali XL; 2007 GMC Savana, Savana HD, Sierra Classic HD; 2001-2002 Workhorse Chassis; with Hydra-Matic 4L80-E or 4L85-E (RPO'S MT1, MN8) SERVICE INFORMATION This bulletin is designed to provide easy to follow valve body reconditioning instructions and new illustrations to simplify reassembly of the valve body, and list other service information documents that are related to the 4L80X transmission family. Related Service Document PIP3427A - SES light on, DTC P0757, harsh shifts, delayed 2-3 shift, no third gear or slip in third or reverse, or a 2-3 shift flare. Debris stuck in the #11 check ball, or a sticking pintle in the 2-3 shift solenoid. Inspection Procedure 1. Using the exploded view (Illus. A), inspect each bore for freedom of valve(s) movement and evidence of debris. Pay particular attention to those valves related to the customer's concern. IF VALVE BODY CLEANING IS NOT REQUIRED, DO NOT DISASSEMBLE BORES UNLESS IT IS NECESSARY TO VERIFY MOVEMENT OF VALVES. 2. Verify movement of the valves in their normal installed position. Valves may become restricted during removal or installation. This is normal due to small tolerances between the valves and bores. 3. If a valve is restricted and cannot be corrected by cleaning the valve and bore, then replace the valve body. Describe the restricted valve on the repair order. Disassembly/Reassembly

Page 2 of 8 1. If a valve is restricted by a metal burr from machining that bore, remove the valve and burr, then inspect movement in the valve's normal position. If no other debris or restrictions are found, then reassemble the valve body and install in the transmission. 2. If the valve body has been contaminated with debris from another transmission component failure, then disassemble all bores for complete cleaning of all valve body components. Keeping individual bore parts separated will make reassembly easier. Use the following illustrations for positive identification and location of individual parts. 3. Using GM Brake Clean, or equivalent, in a safe and clean environment (clean aluminum pan), clean the valve body and dry it with compressed air. Use appropriate eye protection. 4. Clean individual valve body components with GM Brake Clean, or equivalent. Coat each valve with clean ATF and reassemble in each bore. Check each valve for free movement during assembly of each bore. IMPORTANT: Position the valve body as shown in the following illustrations for positive identification and location of individual parts.

Page 3 of 8 Fig 1: View Of Left Side Control Valve Body Assembly Courtesy of GENERAL MOTORS CORP. Call Out For Previous Graphic Call Out Number Description

Page 4 of 8 301 Body, Control Valve 302 Filter, Pressure Control Solenoid Valve Fluid 303 Pin, Shift Valve, Fluid Filter Bore Plug 304 Seat, Low-Reverse Ball Valve 305 Valve, Low-Reverse Ball 307 Seal, 3rd Ball Valve Bushing 308 Valve, 3-4 Shift 309 Spring, 3-4 Shift Valve 310 Bolt, Solenoid (1-2 and 2-3 Shift Valve) 311 Valve Assembly, 2-3 Shift Solenoid 312 Valve, 2-3 Shift 313 Valve Assembly, 1-2 Shift Solenoid 314 Valve, 1-2 Shift 315 Spring, 1-2 Shift Valve 316 Plug, Shift Valve Fluid Filter Bore 317 Filter, Shift Solenoid Valve Fluid 318 Pin, Low-Reverse Ball Valve Seat 334 Bushing, Reverse Ball Valve 335 Bushing, 3rd Ball Valve

Page 5 of 8 Fig 2: View Of Right Side Control Valve Body Assembly Courtesy of GENERAL MOTORS CORP. Call Out For Previous Graphic Call Out Number Description

Page 6 of 8 301 Body, Control Valve 303 Pin, Accumulator Valve Bore Plug, Shift Valve 310 Bolt, Pressure Control Solenoid Clamp 319 Valve, Manual 320 Valve Assembly, Pressure Control Solenoid 321 Clamp, Pressure Control Solenoid 322 Retainer, TCC PWM Solenoid Valve 323 Valve Assembly, TCC PWM Solenoid 324 Valve, TCC Regulator Apply 325 Spring, TCC Regulator Apply Valve 327 Spring, Actuator Feed Limit Valve 328 Valve, Actuator Feed Limit 329 Plug, Accumulator Valve Bore 330 Spring, Accumulator Valve 331 Valve, Accumulator 333 Retainer, Actuator Feed Limit Valve Spring

Page 7 of 8 Fig 3: Control Valve Body Spring and Bore Plug Chart (Metric) Courtesy of GENERAL MOTORS CORP.

Page 8 of 8 Fig 4: Control Valve Body Spring and Bore Chart (Inch) Courtesy of GENERAL MOTORS CORP.