Bonneville V6-231 3.8L (1984)
Planetary Gears: All Technical Service Bulletins
A/T - Loss of Reverse/2nd and 3rd Gear Ranges
Number
84-7-48
Date
10/85
Subject:
STRIPPED INPUT DRUM SPLINES RESULTING IN A LOSS OF REVERSE, SECOND AND/OR THIRD GEAR RANGES
1984 AND EARLIER THM 200-C AND 200-4R TRANSMISSION
INPUT DRUM ASSEMBLY
Some 1984 and prior model THM 200-C, and 200-4R transmissions may have stripped input drum splines resulting in a loss of reverse, second and third
gear ranges (refer to illustration). In mid 1984 production, the drum was hardened in the spline area to prevent the possibility of this occurrence.. The
hardened drum (part number 8648360) may be recognized by a black appearance from the heat treat process.
Anytime a THM 200-C or 200-4R is disassembled, it is recommended that the input drum be replaced with the new hardened input spline drum (part
number 8648360).
Refer to the appropriate Service Information Manual for proper installation procedures.
