1ST OR REVERSE CLUTCH CHATTER REPOSITION 'CROSS SHAFT'. GMC Truck S15 Pickup - 2WD 1982

For 1990-2009 cars

# 1ST OR REVERSE CLUTCH CHATTER REPOSITION 'CROSS SHAFT'

#### MODELS: 1982 AND 1983 S/T MODELS WITH MANUAL TRANSMISSIONS AND V-6 ENGINES

Some 1982 and 1983 S/T models equipped with manual transmissions and V-6 engines may experience a clutch "chatter" or "shudder" when starting out in first gear or reverse. Units diagnosed as having clutch related "chatter" may be corrected by repositioning the frame mounted cordon shaft bracket, sometimes referred to as the "cross shaft" bracket, from the left hand frame rail to the cab toe panel. (See Figure No. 1).

#### NOTE: The nature of this revision requires the technicians to form the new part number 14030840 bracket to conform with the toe pan surface. Special care should be used in step 5 to ensure a good mating between bracket and toe pan surface. Note the "third" bolt location; it is equally important. (See Figure No. 1)

#### PARTS INFORMATION

#### 2-WHEEL DRIVE

Qty. P/N Description ----- --- ----------- 1 14030840 Bracket 1 14063015 Large Spacer 2 11504286 Bolt with Washer 1 14063014 Small Spacer

#### 4-WHEEL DRIVE

Qty. P/N Description ----- --- ----------- 1 14030840 Bracket 1 14063015 Large Spacer 2 11504286 Bolt with Washer

Standard Hardware for 2-Wheel Drive: One 5/16 inch bolt, 2-1/2 inches long, 280M hardness, fine thread with lock washer and nut

Standard Hardware for 4-Wheel Drive: One 5/16 inch bolt, 2 inches long, 280M hardness fine thread with lock washer and nut.

#### SERVICE PROCEDURE

1. Disconnect battery.

2. Pull carpeting or mat and floor insulation inside of cab, back to expose floor pan in area of clutch pedal.

3. Raise vehicle and remove left front wheel and inner fender panel. (Some units will have cruise control mounted on inner fender panel.) Remove all attachments before pulling inner fender out of wheel opening.

4. Disconnect clutch cables from cordon shaft. Remove cordon shaft retaining nut and washer. Cordon shaft can now be pulled free and laid aside.

#### NOTICE: Do not remove frame mounted cordon shaft bracket. It will be necessary to use the existing bracket to locate and position the new bracket so as to maintain cordon shaft to engine alignment.

5. With the cordon shaft removed and the original frame mounted bracket in place, shape the new P/N 14030840 bracket to conform to the toe panel contour. (Refer to Figure No. 1). This can be done with a heavy hammer and vise. For the most part, forming will consist of flatting the 45 degree radius just below the two existing bolt holes. The toe pan area will vary from one truck to another making each bracket require individual forming. Close attention in forming bracket to toe pan is necessary to ensure a good mating surface.

#### NOTICE: Bracket must lay flat against toe pan as shown in Figure No. 1 to ensure proper load distribution.

6. Using the newly formed bracket as a drilling template and the existing frame mounted bracket to locate cordon shaft in its original location, scribe or mark the two hole locations in toe pan for drilling.

7. Remove the original frame mounted bracket and reinstall the frame bolts to secure brake line clips.

8. Drill the two 3/8 inch marked holes in toe pan and install the two 11504286 bolt and washer assemblies from inside of cab. If standard bolts and flat washers are used, make sure the flat washers are at least 1 inch in diameter to ensure bolt load is evenly distributed at toe pan.

9. (VERY IMPORTANT) 3RD BOLT LOCATION: The third bolt is not listed in parts information due to differences in pinch weld dimension. The third bolt hole and bracket should be drilled with a 1/8 inch pilot hole to ensure bolt will secure bracket to pinch weld. After pilot hole is drilled and alignment is correct, drill and install bolt, washer, nut, and lock washer, depending on the dimension of the pinchweld. Check bracket to toe pan mating surfaces to ensure good contact. Flat steel washers can be used to shim between the bracket and pinch weld to prevent stressing the toe pan and bracket.

10. Figure No. 2 illustrates the addition of weight to the cordon shaft lower arm. The addition of weight is used to dampen sound. The installation will differ with 2-wheel and 4-wheel drive units in that the weights will have to be positioned so that they don't interfere with the linkages, exhaust pipe, or in the case of 4-wheel drive, the front driveshaft.

2-WHEEL DRIVE MODELS (SEE FIGURE NO. 2)

a) Drill a 5/64 inch retainer (pin) hole through the 2-1/2 inch long 5/16 inch bolt, 1/8 inch from the end.

b) Drill an 11/32 inch hole through the 14063015 large spacer 3/8 inch from the O.D. Note hole location in Figure No. 2.

4-WHEEL DRIVE MODELS (SEE FIGURE NO. 3)

a) Drill a 5/64 inch retainer (pin) hole through the 2 inch long 5/16 inch bolt, 1/8 inch from the end.

b) Drill an 11/32 inch hole through the 14063015 large spacer 3/8 inch from the O.D. Note hole location in Figure No. 3.

c) Using a hacksaw, cut a notch in the 14063015 large spacer as shown in Figure No. 3. Since the small spacer is not used on 4-wheel drives, the notch allows clearance for the contour of the lower arm on the cordon shaft.

11. Place cordon shaft back in position and hand tighten washer and nut to toe pan mounted bracket.

12. Reinstall clutch pedal cable with original pin, washer, and clip.

13. Place 5/16 inch bolt through off set hole in large spacer 14063015. For 2-wheel drives, next place small spacer 14063014 on bolt through existing center hole. Place bolt through hole on lower arm of cordon shaft as shown in Figures No. 4 or No. 5. Install lock washer and nut. Torque nut down to collapse lock washer while still being able to rotate large spacer weight.

14. Install clutch release cable, washer, and retainer pin.

15. Replace carpeting and insulation inside of cab.

16. Torque cordon shaft nut to toe pan mounted bracket 20-30 N.m (20 ft lb.).

17. Check pedal travel vs. clearance between spacer and exhaust pipe. Rotate the large spacer to clear exhaust pipe and, on 4-wheel drive vehicles, the driveshaft. Torque the jam nut down to lock spacers in correct position. Recommended torque is 20-25 N.m (17 ft lb.).

18. Adjust clutch cable at transmission clutch release lever. Replace wheel inner fender and attaching parts.

19. Road test for proper clutch operation.

#### WARRANTY INFORMATION

Dealers should submit an accurately filled out warranty repair order on each vehicle completed in accordance with this bulletin.

Labor Time Operation Allow- Trouble Number Description ance Code ------ ----------- ---- ---- T3265 Relocate frame 2 Hr. 41 mounted cordon shaft bracket to toe pan.

#### NOTE: This is for all S/T models only.

Some trucks may still exhibit clutch chatter after completing the described revision. If this is the case, it will be necessary to remove and inspect the clutch pressure plate and disc assembly.

If the clutch is found to be wom or warped, it should be replaced.

#### NOTICE: Be sure to inspect the flywheel for warpage and heat checking.

Follow procedures outlined in the Light Duty Service Manual for clutch removal and replacement.

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.