Bravada V6-262 4.3L VIN Z (1991)
Valve Body: All Technical Service Bulletins
A/T - 4L60 Inoperative or Binding In Reverse
NUMBER:
91-T-115
CORP.REF.NO.: 977143R
DATE:
May 1991
SECTION:
7A, 4L60
SUBJECT
BINDING OR INOPERATIVE IN REVERSE
STUCK 4-3 SEQUENCE VALVE AND/OR 2-3 SHIFT VALVE
MODELS/YEARS
1991 BRAVADA AND CUSTOM CRUISER EQUIPPED
WITH HYDRA-MATIC 4L60 TRANSMISSION (RPO-MD8)
This bulletin covers service Information for 1991 HYDRA-MATIC 4L60 transmissions which may exhibit a binding in reverse condition. (The vehicle
would feel as though the engine were being "brake torqued" if reverse range was selected.)
Figure 1
SERVICE PROCEDURE:
When servicing a HYDRA-MATIC 4L60 transmission for a binding in reverse condition, remove the control valve assembly and inspect the 4-3
sequence valve and the 2-3 shift valve. Refer to Figure 1. Either valve, if stuck in the upshifted position, will result in a binding condition. To correct this
condition, the valve body must be completely disassembled and reconditioned according to procedures contained in the HYDRAMATIC 4L60 Unit
Repair section of the appropriate Service Manual.
Inspect the transmission bottom pan for clutch material or burned fluid. Evidence of this will necessitate further transmission diagnosis. Repairs may
include complete transmission reconditioning, including disassembly and reconditioning of the transmission pump and possible torque converter
replacement.
Complete the cleaning of the hydraulic circuit by changing the transmission fluid and filter and flushing the transmission cooler and cooler pipes.