TMR0028 is a downflow radiator for the Mack RD.
The core measures 28.6875" high by 34.375" wide, 2.25" deep. It has a 2" inlet at the left and a 2.5" outlet at the left. There is no integral oil cooler and no filler neck.
It replaces 20 OEM and aftermarket numbers, among them 730039, 730039BT, 621RA039. Searching any one of them will find this part.
On radiators the inlet and outlet positions, and whether the unit carries an oil cooler, decide interchangeability more often than core size does. Two radiators with identical cores are frequently not interchangeable.
