Replacing the control valve body on the 10-speed automatic transmission (RPO MHS, MHT, MHW, MHX, MQA, MQB, MQC, MQL) with the auto engine stop/start feature, available on 2019-2020 CT6; 2019-2022 Silverado, Sierra; 2020-2022 CT4, CT5; 2021-2022 Tahoe, Suburban, Yukon and Escalade models, requires the 10-Speed Transmission Auxiliary Pump Seal Kit. The kit includes two types of seals for the outlet pipe. Only one seal is required, depending on the outlet pipe connection in the service valve body. (Fig. 9)
Fig. 9
The seal for the auxiliary fluid pump outlet pipe must be replaced when installing a new control valve body. The seal (Fig. 10, #2), which is located at the connection of the outlet pipe to the valve body (Fig. 10, #3), is not included with the new valve body.
Fig. 10
Tube-Style Aux Pump Seal
There are two seal designs. The early application has a tube-style seal and the outlet pipe connection on the valve body has a deep design. (Fig. 11)
Fig. 11
O-Ring-Style Aux Pump Seal
The later application has an O-ring seal. The outlet pipe connection on the valve body has a shallow design. (Fig. 12)
Fig. 12
All control valve bodies, including those for past model year vehicles, are switching to the new design seal. However, some low-volume applications still have the early design valve bodies for service.
The 10-Speed Transmission Auxiliary Pump Seal Kit, PN 24047734, includes all parts for both designs. Always refer to the GM Global Electronic Parts Catalog (EPC) for the latest part numbers and related information.
– Thanks to Mark Gordon
