Jim Smart
August 1, 2009
Jaime frees up the intermediate band and reverse/high clutch and forward clutch packages, which are the first items to come out through the front. Inside the reverse/high clutch are composition steel and friction clutches along with a clutch piston that engages them under pressure. For proper operation, good friction is needed.

Valve Body
If you're rebuilding a C4 to stock specifications, all your valve body should need is a thorough cleaning and inspection. Valve pistons should be checked for smooth operation-a nice, smooth glide back and forth with no resistance. Springs and check balls should be replaced as necessary. If you desire a firm shift, TCI Automotive has complete performance valve bodies and shift kits. Ask for the #522100 performance valve body.

ApplicationShift Improvement Kit
1965-1966No. 526000
1967-1969No. 526100
1970-UPNo. 526200
When Should Your C4 Upshift?
D1/Minimum Throttle with 3.00:1 or 3.25:1:1-28-10 mph
D1/Maximum Throttle with 3.00:1 or 3.25:11-231-41 mph
D1/Minimum Throttle with 2.{{{80}}}:1 or 2.79:11-29-11 mph
D1/Maximum Throttle with 2.80:1 or 2.79:11-236-44 mph
D1/Minimum Throttle with 3.00:1 or 3.25:12-312-24 mph
D1/Maximum Throttle with 3.00:1 or 3.25:12-354-71 mph
D1/Minimum Throttle with 2.80:1 or 2.79:12-314-25 mph
D1/Maximum Throttle with 2.80:1 or 2.79:12-364-76 mph