I have a pair of Tie Rods salvaged from a No. 4. The Bottom Frame Assy drawing denotes the Front Tie Rod as p/n MR-104 and the Rear Tie Rod as p/n MR-105; the Front one appears longer. The two parts I have are identical, with the length being 21-7/8″. On my own No. 4, the front rod measures 22-1/2″ and the rear 21-1/8″. Why the differences, and does any of this matter?
The two identical tie rods are MR-113 for the top frame assembly. See Sheet 102A of your manual. The difference in length between the two bottom frame tie rods is to fit their stops on the roller trip assembly. So the difference in length does matter.