Trying to set the clearance in a Forward Clutch. The following pic is the Backing Plate (GM Service pic# 646) laying in a 1986 Input Drum, resting on the tabs in the Input Drum. This Backing Plate has 4 tabs on the inner edge. They do not touch anything. They do not interface with anything. I would like to use the 1987-up selectible thickness Backing Plates to set the clutch stack clearance, but the 1987-up Backing Plates do not have the 4 tabs. The tabs are actually in the same plane as the plastic Thrust Washer (GM Service pic #660), not the Forward Clutch/Sprag Outer race (GM Service pic#644). With the Backing Plate (646) bottomed in the drum, on the drum tabs, it does not touch the Sprag Race (644). The 1987-up also uses a different Forward Sprag Assembly (includes #644). I also installed the Input Sun Gear (658) and the Input Carrier (662) which do not interface with the 4 tabs although the Carrier (662) does rest on the plastic Washer (660). Does anyone know what the purpose is for the 4 tabs? Can I use the 87-up selective thickness Backing Plates? As it stands, I'm planning on dicking around with combinations of .078 and .090 regular Steels to set the clearance.
http://i43.tinypic.com/o51dmt.jpg
Tom
06-25-2013, 07:17 AM
