A/T - 440T4 Converter Regulator Valve

TSB 88-21 (May)

SUBJECT: Converter Regulator Valve

THM 440-T4




When servicing the THM 440-T4 transmission, it is recommended that you replace the converter regulator valve spring (See Figure 1) with a two pound heavier spring.

This will raise the pressure in the torque converter, and reduce the possibility of TCC chatter.

It's important to note that the factory changed the tension of this spring more than once.

Many of the late 1985 and later transmissions have no spring on this valve, and should have a two pound spring installed.




To weigh the spring, compress the spring with the valve on a scale until the stem of the valve touches the scale, then read the scale. (See Figure 2)

Note
It is recommended that you do not block the valve to the maximum pressure position. This may result in an objectionable TCC engagement.