Firebird V8-305 5.0L (1982)
Valve Body: Customer Interest
A/T - 4L60 Binding or Inoperative In Reverse
Bulletin Number:
91-7-30
Reference Number:
977143R
Publish Date:
4/91
Subject:
BINDING OR INOPERATIVE IN REVERSE - STUCK 4-3 SEQUENCE VALVE AND/OR 2-3 SHIFT VALVE
Models Affected:
1982-91 ALL MODELS WITH 700-R4 (4L60)
This bulletin is being revise to add the 1991 model year and information concerning the bolt tightening pattern. This bulletin cancels and replaces
bulletin 89-7-48 issued 10/89. Please discard bulletin 89-7-48.
This bulletin covers service information for 1982 through 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 - Control Valve Assembly
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 HYDRA-MATIC
4L60/THM 700-R4 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.
