I have a C4 I recently picked up to put behind my old 289. I had a working transmission with some leaks so I picked up a new rebuilt C4 for my ride:

number I found on the new transmision:

C4OP-70027-A
C4AP-7A040-C
C6DP-7006A

I tried to install this transmission and there seems to be a gap from the bellhousing to the engine block. So I removed the rebuilt torque converter it seems to be a little bit larger then the previous one (1/4"). I tried to install the trans (with the old torque converter) and again seems like less of an issue but still not bolting on tight to the engine. So I dropped the trans again and installed the original bellhousing and torque converter on the new C4 and still it is not tight against the engine block. I have installed and removed this trans at least 6 times in the last week so I know the converter is seated tight as possible and I have had more then one person check it. Currently the transmission is in the car and there is a 1/4" to 3/8" gap from the block to the bellhousing. The plate between the engine and the bellhousing is pushing out from the torque converter into the flexplate.

numbers on old trans:

C5AP-7006B
C4AP-7A040-0-B
C40P-7D027-A

I have come up with the conclusion that the input shaft on the converter must be a different length on this new transmission.

WHAT THE HECK IS GOING ON?



Craig

 

Could this be your whole issue? Plate should fit flat on block or bell housing when it's apart. Bolt holes aligning up from converter to flexplate?