Not normal switch pitch question.

Ive read a hundred forums and cant find this out. Mt 65 riv has the sp400 but my torque converter with the ispection cover off says d4 stamped all the way around it. The ****** was rebuilt in the mid 80's. Has this converter been swapped out? What the heck is a d4 then? Thanks.

 

No idea about the D4 but you can't swap converters between SP and Non-SP the Front Pump and Input shaft are different.

 

Ok thanks. Just havnt seen anywhere for id'ing one that they say d4 on it anywhere.