HARSH/DELAYED UPSHIFTS/700-R4 ADD ATV EXHAUST CHECK BALL

MODELS: 1984 LIGHT DUTY TRUCKS WITH THM 700-R4 TRANSMISSION

Beginning with the 1984 production, the THM 700-R4 transmission is being produced with a T.V. exhaust checkball in the control valve assembly. The purpose of the T.V. exhaust checkball is to prevent low or minimum line pressure in the event the T.V. cable should break or become disconnected.

This T.V. exhaust checkball is located beneath the throttle lever and bracket assembly. (Figure No. 1, Ill. #91). It is normally held off its seat by the throttle lever and bracket assembly. If the T.V. cable should break or become disconnected, the T.V. exhaust checkball will seat and cause elevated line pressure, causing harsh and delayed upshifts.

When servicing any THM 700-R4 transmission for harsh and delayed upshifts, install a line pressure gage to the line pressure tap location to verify elevated line pressures. If line pressure is elevated, inspect the T.V. cable and the throttle lever and bracket assembly for proper connections. Connect and/or replace the cable or bracket assembly as required.

The 1982 and 1983 tHM 700-R4 transmission sections will show a T.V. exhaust valve in error. The T.V. exhaust checkball went into production in 1984 and was not used in previous years.

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