A/T - 700R4 New Auxiliary Accumulator Valve Body

SIL 87-33 (Oct)

SUBJECT: THM 700 R4

700 R4 with Auxiliary valve body








A new auxiliary accumulator valve body (Figure 1 # 377) and cover (Figure 1 # 371) went into production to prevent the accumulator piston pin from working its way out of the auxiliary valve body. If the accumulator piston pin comes out of either end of the auxiliary valve body, the following conditions could occur.

1. Loss of drive
2. Slipping in drive
3. Burned forward and overrun clutches




Beginning January 27, 1987, (Julian date 027 Figure 2) all the 700 R4 transmissions were produced with an auxiliary accumulator valve body assembly that has a stepped bore at one end of the piston pin, and a new cover with an oval, instead of a round, exhaust hole at the other end of the pin, to retain the accumulator piston pin in place. The new auxiliary accumulator valve body and cover can be used on any 1987 THM 700 R4 transmission that has an auxiliary valve body.

If the accumulator piston pin has come out of the auxiliary valve body, check for burned forward and overrun clutches.