Seal installation depth is critical when replacing the transfer case front input shaft seal between the transmission and transfer case on 2020-2026 Silverado 2500HD/3500HD and Sierra 2500HD/3500HD trucks equipped with the RPO NQF or NQH transfer case. (Fig. 11)
Fig. 11
The transfer case has a gap around the outer portion of the seal that needs to be centered over a weep hole in the transfer case. The weep hole is drilled in the center of a groove machined into the case. (Fig. 12) The DT-50648-A Seal Installer will not work for these applications.
Fig. 12
Two Tools, Two Transfer Case Designs
There are two special tools available, depending on transfer case design, for installing the input shaft seal to the correct depth. The seals are installed at different depths on first design and second design cases.
To identify each design, look for a machined groove where the seal is installed (circled as shown). If there is a defined machined groove in the case, it is a first design case. (Fig. 13)
Fig. 13
If there is not a defined groove machined into the case, it is a second design case. (Fig. 14)
Fig. 14
First Design Transfer Case
For the first design transfer case used on early 2020 model year vehicles, refer to Transfer Case Assemble (VIN LF263576 and Earlier – with MGM or MGU) in the Transfer Case – Off Vehicle repair instructions in the 2020 model year Service Information. Seal installer DT-53017 (GM-53017) should be used for these applications.
The DT-53017 tool is currently available to order and also is available through the Loan Tool Program.
Second Design Transfer Case
For the second design transfer case, which was introduced later in the 2020 model year and used on 2020–current model year vehicles, follow either the Transfer Case Assemble (VIN LF263577 and Later – with MGM or MGU) in the Transfer Case – Off-Vehicle repair instructions in the 2020 model year Service Information or the year of the vehicle being repaired. The DT-53018 (GM-53018) Seal Installer should be used for these applications. (Fig. 15)
Fig. 15
The DT-53018 tool is an Essential tool and will be identified as GM-53018. It will begin being shipped to all dealerships that have not already purchased the tool.
To install a new transfer case input shaft seal (Fig. 16, #3), use the J-8092 Driver Handle (Fig. 16, #2) and DT-53018 Transfer Case Front Input Shaft Seal Installer (Fig. 16, #1).
Fig. 16
TIP: Using the incorrect tool will create a repeat leak as the seal may not be at the correct depth or may not be installed straight.
The tools can be ordered through the GM Special Tools and Equipment website at gmglobaltools.com.
For more information, refer to #PIP5810C.
– Thanks to Steve Underwood
