PULLEY GP-FAN & ALT DRIVE 3233269 - Caterpillar

769C Trucks And 771C Quarry Trucks
Valve Modification
Effective with 769C (01X6600-6981) and 771C (3BJ200-257). The 7J-8307 Valve has an orifice diameter of 5.15 mm (.203 in). In the past this same 7J-8307 Valve was installed to limit the body "raise" time (see Illustration 1.). Installation of the 7J-8307 Valve in the opposite direction (see Illustration 2.) will significantly reduce the impact of the body on the chassis when lowered. However, a delay in transmission up shifts on trucks equipped with the body up shift limiter may also be noted. If this is noted the 7J-8307 Valve orifice can be drilled as required up to a maximum diameter of 6.00 mm (.236 in) to lessen this delay and still lower the impact from the body contacting the chassis.
Illustration 1. View of former valve installation.
Illustration 2. View of reversed valve.
Illustration 3. View of orifice to be modified.Orifice Plate Modification
Effective with 769C (01X06982) and 771C (3BJ00258), the former hoist cylinder valve was replaced by 126-0293 Orifice Plate with a center orifice of 8 mm (.3 in) . To slow the body down with the use of an orifice plate, take two (2) 8X-3572 Plates and enlarge the 4.00 mm (.157 in) hole in the center of this plate as required with a drill to a maximum of 6.00 mm (.236 in). Remove the 126-0293 Orifice Plates from the bottom ports of the cylinders and replace with the "modified" 8X-3572 Orifice Plates.
773B Trucks And 775B Quarry Trucks
Valve Modification Only
Remove the 7J-0413 Valve with an orifice of 9.5 mm (.37 in) from the 9J-2017 Cylinder Group and replace it with a "modified" 9M-5549 Valve which has been drilled out to a minimum of 8.40 mm (.331 in). The 9M-5549 Valve has a normal orifice size of 7.9 mm (.31 in).