GRUNT/SQUAWK NOISE-NEW DESIGN YOKE SLEEVE TO AXLE SHAFT

Subject: GRUNT OR SQUAWK NOISE (LUBRICATED YOKE SLEEVE TO AXLE SHAFT) 4L80-E NEW SERVICE PACKAGE

Model and Year: 1991 C1 TRUCKS WITH 4L80-E AND 7.4L ENGINE AND G313 VAN WITH 4L80-E/4L80-EHD

Some HYDRA-MATIC 4L80-E/4L80-EHD transmissions may experience a grunt or squawk noise coming from the output shaft area. This noise is caused by the prop shaft moving back and forth on a non-lubricated transmission output shaft. A new Output Shaft Assembly was released which adds a greased sleeve to lubricate the yoke to output shaft area and dampens the noise.

A new propshaft shaft assembly was released which has grease added to slip yoke splines, a vented welsh plug and slight increase in length.

New Models, which feature this grease sleeve, were released to replace current models:

Previous Models New Models --------------- ---------- AJP ADP BRP BBP CSP CBP HSP DDP HTP DSP

Date of Production Change: (Figure 1) -------------------------------------- Starting May 13,1991 (Julian Date 133), all HYDRA-MATIC 4L80-E/ 4L80-EHD AJP, BRP, CSP, HSP, and HTP models were built with the new Greased Sleeve.

Service Parts Information:

Part Number Part Description ------------- -------------------------------- 8683922 Package, Sleeve and Seal Assembly Output * 8661596 Shaft and Bushing Assembly - Output 15679617 Propshaft (model C1 with L19) 15679625 Propshaft (model G31305/6 with LB4/L05/LL4 and MT1 model G31303- 32 with L05/LL4 and C6P) 15679626 Propshaft (model G31305/6 with L1 9 model G31303-32 with C6P and L19 model G31303-32 with C6S/C7A/C70) 12345879 Lubricant, Special

* If the output shaft journal is not finished (ie. built before November 12, 1990 (Julian Date 316)), then a new Output Shaft Assembly must be installed. Transmission must be removed from vehicle in order to replace Output Shaft Assembly with machined journal.

Parts are expected to be available on 8/19/91. Until then normal part orders will not be accepted by GMSPO. In an emergency, contact your division service department for the required parts order authorization.

On-Vehicle Service Procedure: (Figure 2,3, and 4) -------------------------------------------------- The output shaft journal must be machine finished in order to install the new sleeve. (Figure 4)

1. Remove propshaft from transmission output shaft.

2. Remove transmission extension assembly.

3. Install the new service package onto output shaft journal.

4. Lightly coat splines of transmission output shaft with grease (P/N 12345879) to completely cover the entire spline.

5. Reinstall extension assembly.

6. Apply grease (P/N 12345879) to slip yoke of new propshaft with brush or swab, so as to completely cover the entire spline with a light coating of grease.

7. Reconnect new propshaft.

Service Manual Reference:

Refer to the Unit Repair Service Manual Section 7 for proper replacement procedures for Output Shaft Assembly and appropriate service manual section for propshaft replacement.

Figure 3 - Internal Components - Legend

530 PLUG, ORIFICE CENTER SUPPORT 537 BALL, CHECK 601 BEARING ASM., THRUST CARRIER/FORWARD CLUTCH 602 HOUSING ASSEMBLY, FORWARD CLUTCH 603 SEAL, CLUTCH (CENTER) 604 SEAL, CLUTCH (OUTER) 605 SEAL, CLUTCH (INNER) 606 PISTON, FORWARD CLUTCH 607 SPRING & RETAINER ASSEMBLY 608 RING, SNAP 609 PLATE, CLUTCH (.054 DISHED) 610 PLATE, CLUTCH (.0775 FLAT) 611 PLATE ASSEMBLY, CLUTCH 612 WASHER, THRUST CLUTCH HUB HOUSING 613 HUB, FORWARD CLUTCH DRIVEN 614 WASHER, THRUST FORWARD CLUTCH 615 HUB, DIRECT CLUTCH DRIVING 616 RING, SNAP (6.24 O.D. X.062) 617 PLATE, DIRECT CLUTCH BACKING 618 PLATE, CLUTCH (.0915 FLAT) 619 PISTON, DIRECT CLUTCH 622 SEAL, CLUTCH (CENTER) 623 HOUSING, DIRECT CLUTCH 624 SPRAG ASSEMBLY, INTERMEDIATE CLUTCH 625 RACE, INTERMEDIATE CLUTCH (OUTER) 626 RETAINER, INTERMEDIATE CLUTCH 627 RING, EXTERNAL LOCKING 628 BAND ASSEMBLY, FRONT 629 RING, SNAP (INTERMEDIATE CLUTCH RETAINER) 630 PLATE, INTERMEDIATE CLUTCH BACKING 631 PLATE ASSEMBLY, INTERMEDIATE CLUTCH 632 PLATE, INTERMEDIATE CLUTCH 633 RING, SNAP CENTER SUPPORT/CASE 634 RING, SNAP INTERMEDIATE CLUTCH 635 SPRING & RETAINER ASM., INTERMEDIATE CLUTCH 636 PISTON, INTERMEDIATE CLUTCH 637 SEAL, INTERMEDIATE CLUTCH (INNER) 638 SEAL, INTERMEDIATE CLUTCH (OUTER) 639 RING, OIL SEAL 640 SUPPORT & RACE ASSEMBLY, CENTER 642 WASHER, THRUST SUPPORT/REACTION DRUM

643 SPACER, SUPPORT TO CASE 644 ROLLER CLUTCH ASSEMBLY 645 RING, REACTION DRUM SPACER 646 RACE, THRUST BEARING TO CENTER SUPPORT 647 BEARING, NEEDLE THRUST 648 RACE, THRUST BEARING 649 SHAFT ASSEMBLY, SUN GEAR 650 GEAR, SUN 651 DRUM & CARRIER ASSEMBLY, REACTION 652 WASHER, PINION THRUST (BRONZE) 653 WASHER, PINION THRUST (STEEL) 654 ROLLER, NEEDLE BEARING 655 PINION, PLANET 656 PIN, PLANET PINION 657 BAND ASSEMBLY, REAR BRAKE 658 RING, FRONT INTERNAL GEAR 659 WASHER, FRONT INTERNAL/REACTION CARRIER 660 RING, OUTPUT SPEED SENSOR 661 CARRIER ASSEMBLY, OUTPUT 662 SHAFT, TRANSMISSION MAIN 663 RACE, THRUST BEARING TO SUN GEAR 664 BEARING, NEEDLE THRUST RR INTERNAL GEAR 665 RACE, THRUST BEARING TO RR INTERNAL GEAR 666 GEAR, REAR INTERNAL 669 RACE, THRUST BEARING TO OUTPUT SHAFT 670 RING, SNAP MAINSHAFT INTERNAL GEAR 671 SHAFT & BUSHING ASSEMBLY, OUTPUT 672 RING, SNAP (OUTPUT SHAFT/ FRONT INTERNAL GEAR) 673 WASHER, THRUST 674 WASHER, THRUST SELECTIVE 675 SEAL, O-RING OUTPUT SHAFT 676 BUSHING, SUN GEAR SHAFT 677 BUSHING, OUTPUT SHAFT 678 BUSHING 679 BUSHING, 1.536' DIA. X 3.52' 680 BALL, CHECK 681 BUSHING, REACTION DRUM 682 SLEEVE, TRANS. OUTPUT SHAFT YOKE SEAL 683 SEAL, OUTPUT SHAFT

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.