Fuel Transfer Pump Compatible With John Deere 4320/4520/4620 1972-1987 6.404D 6.6L Diesel 2-Bolt

TRACTOR:
• John Deere 4320/4520/4620/4720 6.404D 6.6L Diesel (1972-1987)
• John Deere 7020 6.404D 6.6L Diesel (1972-1987)

HARVESTER:
• John Deere 5200/5400 6.404D 6.6L Diesel (1972-1982)


IMPORTANT:
Mechanical fuel transfer pump — 2-BOLT mount, PLAIN style (no O-ring seal, no threaded fittings). For John Deere 6.404D engine with serial number BELOW 335,846. This serial number break is the #1 ordering mistake. One of THREE 400 Series variants — ordering the wrong one is extremely common:
- TAR49771: 2-bolt plain (this pump) — older engines, s/n below 335,846
- TAR57264: 2-bolt WITH O-ring — newer engines, s/n 335,846 and above
- TAR53567: Threaded fittings — earliest models (3010/3020/4010/4020)
Failure symptoms: fuel weeping from pump body, hard starting, loss of power on hills, engine dying under load. Cam-lobe driven — inspect cam lobe for wear during replacement. Replace mounting gasket and prime system before starting.
⚠️ Check engine serial number to determine correct variant (plain, O-ring, or threaded).