I think fj40 usually uses H41 and H42 , when those engines born it may found a H,B,2B,3B,F155,F,2F but when realizes about fitting 2h could be H42 transmission or H55F trans, but those use another bellhousing and input shaft may became different splines.( usually when HJ45 comes to pre 1977 uses coarse input shaft, but 1978 may uses a fine input shaft )..Conclusions : may you wish withstand using HJ45 = H engine H41 or H42 , but not H55F ...if 2H engine H42 or H55F. Best Regards!