C 1500 Truck 2WD V6-262 4.3L VIN Z (1992)
Shifter M/T: All Technical Service Bulletins
M/T - Shift Lever Shake/Noise in 2ND Gear
BULLETIN NUMBER: 93-7B-26
SECTION: 7B
NUMBER: 1
CORPORATE
REFERENCE NUMBER: 267204R
DATE: November 1992
SUBJECT:
SHIFT LEVER SHAKE AND/OR NOISE IN 2ND GEAR (SERVICE PROCEDURE)
MODELS:
1991-93 C/K, P TRUCKS WITH NV4500 (RPO MT8) 5 SPEED MANUAL TRANSMISSION
Some owners of 1991-93 C/K, P trucks equipped with a NV4500 (RPO MT8) 5 speed manual transmission may comment that their vehicle experiences
shift lever shake and/or transmission noise when the shift lever is in 2nd gear as labeled on the shift knob.
This condition may be caused by wobble in the shift sleeve (94) which results in noise as the sleeve (94) contacts the shift fork (11) and/or lever shake if
the shift sleeve (94) wobble is great enough. This condition may be corrected by replacing the three/four synchronizer assembly (91-94), the 3rd speed
gear (87/89), the main drive clutch gear (95) and the shift cover assembly (8). The synchronizer and gears have revised teeth for improved mating and
the cover features a revised detent in the 3-4 shift rail to reduce lever shake.
VEHICLES INVOLVED
Some 1991-93 C/K, P trucks equipped with a NV4500 5 speed manual transmission built prior to the following VIN breakpoints:
GMC
Detroit (3)
P3500000
Ft. Wayne
(Z)
PZ500000
Janesville
(J)
3500 HD
PJ500012
Crew Cab
PJ701238
Oshawa (1)
P1507216
Pontiac (E)
PE503845
SERVICE PROCEDURE
Refer to the appropriate Unit Repair Manual (Section 7B2, New Venture Gear 4500 Manual Transmission) for Unit Disassembly and Assembly and
Mainshaft Disassembly and Assembly. Follow the procedures listed to:
-
Remove the mainshaft assembly (57-94) from the transmission.
-
Remove the three/four synchronizer assembly (91-94) from the mainshaft.
-
Remove the third speed gear (87/89) from the mainshaft.
-
Install the new third speed gear (87/89)
-
Install the new three/four synchronizer assembly (91-94)
Important
A new synchronizer assembly can change mainshaft endplay. Endplay should be checked and must be .002" - .006". Change mainshaft bearing shims
(141) as required.
-
Install the new main drive clutch gear (95) to the main drive gear (98).
-
Install a new shift cover assembly (8). This new cover requires the installation of a new vent tube (52) and new reverse fork pads (12). Transfer the
shift stub lever assembly including the boot seal (1-4), and back-up switch and gasket (50-51) from the previous cover.
