Usage:
D342, D343 Engines in All Applications;
1693 Truck Engines
Description of Change: A new front seal and wear sleeve are used in crankshaft groups for the above engines. This permits repair of worn surfaces for maximum seal efficiency, without installation of a new crankshaft. To give the necessary clearance for the wear sleeve, the opening for the crankshaft in 9L6017 and 9S745 Front Covers (Cylinder Block) now has a larger bore diameter.
Adaptable To: The new 9N2539 Seal and 9J110 Wear Sleeve can be installed in place of the former 2S1509 Seal in all earlier engines. The new seal and sleeve are available in a 7N142 Seal Group (Crankshaft Front) for service replacement. On engines equipped with the 9L6017 or 9S745 Cylinder Block Front Cover, it will be necessary to either install a later front cover or machine the opening for the crankshaft in the existing cover to a diameter of 4.400" ± .010" (111.76 ± 0.25 mm). The part numbers of the 9L6017 and 9S745 Front Covers are not changed, but identification of the later covers can be made by measurement of the crankshaft hole diameter. The former diameter was 3.740" ± .010" (95.00 ± 0.25 mm).
INSTALLATION: Complete instructions for installation of the crankshaft seal and wear sleeve are given in Special Instructions Form SMHS6959.