W350 1 Ton Pickup 4WD V8-360 5.9L VIN 1 4-bbl (1988)
Clutch: All Technical Service Bulletins
A/T - A500/A518 Repeat Failures of Overdrive Clutch
Models
1988-90 B/AB, D/AD, & A/AN Bodies
Subject
Repeat Failures Of Automatic Transmission Overdrive Clutch
Index
TRANSMISSION
Date
January 29, 1990
No.
21-01-90
P-151 (C21-26-9)
BODY CODE LEGEND
B/AB - RAM VAN/WAGON (RWD) D/AD - RAM PICKUP/RAM CAB & CHASSIS/RAMCHARGER (RWD, 4WD) POWER RAM CAB &
CHASSIS (4WD)
N/AN - DAKOTA/DAKOTA SPORT/DAKOTA CONVERTIBLE DAKOTA CAB & CHASSIS
THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH THE A500 OR A518 AUTOMATIC TRANSMISSION.
SYMPTOM/CONDITION
Repeated failures of the overdrive clutch.
The A500 and A518 automatic transmissions have a small nylon orifice plug in the overdrive piston retainer. The purpose of this orifice is to bleed line
pressure into the cavity in front of the overdrive piston to keep this cavity full of fluid and at a low residual pressure. This reduces the time required to
make a shift into overdrive.
If this orifice comes out of place, then the residual pressure on the overdrive piston will be high enough to cause the overdrive clutch to drag and burn
up.
REPAIR PROCEDURE
This procedure involves inspecting the orifice for looseness in the overdrive piston retainer.
1.
Remove the overdrive unit from the transmission as outlined in the service manual.
2.
Remove the overdrive piston from the piston retainer on the back of the transmission.
