A/T - Soft 1-2 and Harsh 2-3 Shifts
Bulletin No. T 84-73File In Group 7
Number 103
Date MAY '84
SUBJECT: SOFT 1-2 AND HARSH 2-3 SHIFTS - THM 200C, 200-4R AND 325-4L
MODELS AFFECTED: 1979 SEVILLES 1980-1984 DEVILLES AND BROUGHAMS 1982-1984 ELDORADOS AND SEVILLES
1979 through 1984, Cadillacs equipped with a THM 200C, 200-4R or 325-4L transmission may exhibit soft 1-2 and harsh 2-3 upshifts. This condition may be caused by a hydraulic leak in the seal areas of the intermediate servo outer piston. The affected Cadillac vehicles which may experience this condition are as follows:
Year(s) Vehicle(s) Transmission/Model(s)
1979 Seville THM 200C/AX
1980-1981 Deville and Brougham THM 200C/AS
1981-1984 Deville and Brougham THM 200-4R/AA, BY and OM
1982-1984 Eldorado and Seville THM 325-4L/AJ, AL, AM and AE
FIGURE 1 - NEW RUBBER LIP SEALS:
FIGURE 2 - PAST SCARF CUT TEFLON SEAL RINGS:
Beginning in January, 1984, all models of THM 200C, 200-4R and 325-4L transmissions are being produced using a new intermediate servo outer piston that has rubber lip seals in place of the past scarf cut Teflon ring seals (refer to illustrations). When servicing any of the above listed transmissions for a soft 1-2 and harsh 2-3 upshifts condition, replace the scarf cut seals equipped intermediate servo outer piston with the appropriate new rubber lip seals piston listed below:
Servo Piston Kit P/N's (Includes New Piston and Rubber Lip Seals)
Year(s) Transmission/Model(s) Outer Piston
1979-1980 THM 200C/AX and AS 8638936
1981 THM 200C/AS 8638937
1981-1984 THM 200-4R/AA, BY and OM 8632980
1982-1984 THM 325-4L/AJ, AL, AM and AE 8632980
NOTE: The new rubber lip seals must not be installed on past intermediate servo outer pistons or past Teflon seals on new pistons.
The new rubber seals are also available separately in a service package (P/N 8638941) consisting of two rubber lip seals and a servo cover "O" ring.