C4 Transmission Performance Rebuild - Automatic Authority

Quick Reference Guide to C4 V-8 Bellhousings
Model Year	Casting Number/Ford Part Number	Specifics
’64	C4AP-7976-A and C4AZ-7976-A	Five-bolt bellhousing, 160-tooth flexplate, two-bolt starter, 221, 260, 289 V-8
’65-’69	C5OP-7976-A and C5OZ-7976-A	Six-bolt bellhousing, 157-tooth flexplate, two-bolt starter, 289 and 302 V-8
’72-and-later	D2OP-7976-AA and D2OZ-7976-B	Six-bolt bellhousing, 157-tooth flexplate, case-fill dipstick, two-bolt starter, 302 V-8, cable kickdown
’73-and-later	D3BP-7976-AA and D3BZ-7976-A	Six-bolt bellhousing, 164-tooth flexplate, pan-fill dipstick, two-bolt starter, 302, and 351 V-8
’75-’78	D5ZP-7976-A and D5ZZ-7976-A	Six-bolt bellhousing, 157-tooth flexplate, small torque converter for Mustang II only, case-fill dipstick, two-bolt starter, 302 V-8
’76-’79	D6TP-7976-AA	Six-bolt bellhousing, 164-tooth flexplate, truck only, pan-fill dipstick, two-bolt starter, 302 and 351 V-8
’77-and-later	D9AP-7976-AA	Six-bolt bellhousing, 157-tooth flexplate, case-fill dipstick, cable kickdown, two-bolt starter, 255, 302, 350 V-8
’77-and-later	D7BP-7976-AA and D7BZ-7976-A	Six-bolt bellhousing, 157-tooth flexplate, case-fill dipstick, two-bolt starter, 255, 302, and 351 V-8
’78-and-later	D7DP-7976-AA and D8OZ-7976-B	Six-bolt bellhousing, 157-tooth flexplate, case-fill dipstick, two-bolt starter, cable kickdown, 255, 302, and 351 V-8
’79-and-later	D9AP-7976-BA	Six-bolt bellhousing, 157-tooth flexplate, pan-fill dipstick, cable kickdown, two-bolt starter, 255, 302, and 351 V-8
’79-up	D9AP-7976-AA	Six-bolt bellhousing, 157-tooth flexplate, case-fill dipstick, cable kickdown, two-bolt starter, 255, 302, and 351 V-8
’82-up	E2TP-7976-AA and E2TZ-7976-A	Six-bolt bellhousing, 164-tooth flexplate, trucks only, pan-fill dipstick, two-bolt starter, cable kickdown, 255, 302, and 351 V-8
’75-up	D5OP-7976-BA and D5OZ-7976-A	For 351M and 400M with big-block bellhousing bolt pattern

There are so many types, C4... read full caption There are so many types, C4 bellhousing identification will drive you nuts. Always check casting numbers and the number of bellhousing-to-engine bolt holes just for starters. Check depth, which determines whether you have a 157-tooth or 164-tooth flexplate bellhousing. Ascertain whether the bellhousing is a pump mount or transmission main-casting mount. They will not interchange.	Shift improvement kits from... read full caption Shift improvement kits from B&M Racing & Performance make a difference in how your C4 shifts. Count on a firmer shift, which is important to both performance and reliability. Soft shifts mean excessive clutch and band wear.	Firm shifts come from solid... read full caption Firm shifts come from solid clutch and band engagement. The type of fluid you use also determines shift quality. B&M's Trick Shift automatic transmission fluid has a friction modifier designed to improve clutch and band engagement.
This is the sprag clutch,... read full caption This is the sprag clutch, also known as a one-way clutch. Throw your Ford sprag away, and opt for one from either Mike's Transmission or B&M. Shown here is one from Mike's Transmission, a spring/roller design engineered not to fail.	Deep sump pans are nothing... read full caption Deep sump pans are nothing but good for automatic transmissions. A deep cast-aluminum sump, shown here with a filter-extension feature (mandatory for fluid pick-up), cools fluid better and gives the C4 greater capacity. If racing, a deep pan and a cooler are vital, and for heavy-duty street use, you can't lose because cooler fluid temperatures enhance transmission service life. Average temperature is around 250-300 degrees. When temperatures become higher than this, transmission life shortens quickly.	Another item that stumps enthusiasts... read full caption Another item that stumps enthusiasts is the governor on the tailshaft. The governor reads the transmission-shaft speed, which determines upshift and downshift points. Always check the governor piston for freedom of movement and the spring for integrity. These items must work.