GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 39919-1 Center Support Thread Reamer
    • J 39919-2 Center Support Bore Gage

Object Number: 56542  Size: SH

Important: You may recondition the original center support (640) one time only by using the tools listed above. You must use the new, larger, service bolt with the reconditioned center support in order to avoid component damage. The service bolt is yellow in color, and the production bolt is black in color.

Perform ONE of the following steps:

    • If the center support has been previously reconditioned, or if J 39919-2 fits into the bolt hole, you must replace the center support and bolt in order to avoid component damage.
    • If the center support has never been previously reconditioned:
       - Insert J 39919-2 into the center support bolt hole. If J 39919-2 does not fit into the center support bolt hole, you can recondition the center support for reuse.
       - Ream the center support bolt hole to the proper dimension using J 39919-1 .