4L60E Forward Input Sprag Assembly, 29-Element

This is the 29-element forward (input) sprag that sits between the input sun gear and the forward clutch hub in the input housing. It replaces OE and aftermarket numbers 29236AM, 8654441A, A74658B, A74658C and 77725B, and fits the 4L60E (1993-2014), 700R4 (1987-1992), 4L65E (2001-2007) and 4L70E (2006-2009).

A failed input sprag is a classic cause of no drive in first gear, a slip or flare on the 1-2 in manual low, or drive that only comes back in reverse or manual range. Sprags wear or roll over from heat and hard launches, and the elements get scored so they no longer lock the race. Any time you have the input housing apart with that complaint, check the sprag for freewheel in the correct direction and for chatter marks on the race.

On the bench, note the sprag direction before disassembly, install it so it locks the input sun gear in the same direction, and check the inner and outer race surfaces for pitting. If the races are damaged, the sprag alone will not fix it. The 29-element design is the stock count; builds seeing high torque often step up to a 34-element sprag.