Description

John Deere 6620 1990 Parts Catalog

You pull a part off a John Deere 6620 and the number isn’t readable. Or you’re staring at a bin of bearings and wondering which one matches the separator shaft. Without the factory parts catalog, you’re flipping through aftermarket books that skip serial number breaks and group codes. That’s wasted time and wrong parts. This Parts Catalog from 1990 gives you the exact OEM part numbers, organized by the same grids the dealership uses. 1265 pages of original John Deere documentation.

Serial Number and PIN Plate Location

Page 3 of this catalog shows where the serial number plate lives on early and late 6620 combines. For machines up to serial 551900, the plate is on the rear left-hand upright. Later machines use a two-line Product Identification Number (PIN) near the tool box on the right side. That PIN tells you the model, configuration code, and sequential number. Ignore it and you’ll order parts for the wrong vintage. I’ve seen guys bolt on a later-model feeder house lift cylinder and wonder why the hoses don’t reach. Get the serial number right first.

Engine Serial Number Identification

Right side of the block. The engine serial number plate breaks down the number of cylinders, displacement, fuel type, and engine version. For example, a 6466TH01227599RG means 6 cylinders, 466 cubic inches turbo diesel, Harvester Works assembly, engine version 01, serial 227599. That info matters when ordering injectors, gaskets, or a short block. Aftermarket catalogs often give you a generic number that fits three different engine versions. This manual lists the exact part for your engine serial range.

John Deere 6620 1990 Parts Catalog: 1265 Pages of Factory Data

Every grid in this catalog is tied to a specific assembly on the combine. Sections like 01A through 01I cover the entire machine: from the cab interior (01G) to the rear axle (02E). The grid system, like 01A02 for the feeder house, is the same one used in John Deere’s own parts system. When you call a dealer and give them a grid and item number, they pull the exact part. No guessing. The catalog also includes reference numbers for related attachments like the 653 row-crop head, 200 series platforms, and corn heads. You can cross-reference part numbers across multiple manuals. Related manuals you might need: John Deere 6020-6920S Series Technical Manual – Section: Indx and John Deere 6020 6620 6920S 2002 Technical Manual – Section: Section 99—Special T. For older models, see John Deere 6620 7720 8820 1978 Service Manual.

Why Factory OEM Documentation Beats Aftermarket

Aftermarket parts books often re-edit the illustrations, leave out serial number breaks, or use generic part numbers that don’t match the actual John Deere supersession chain. This is a direct scan of the original PC1666 catalog, printed October 23, 1990. The part numbers haven’t been filtered or simplified. You get the same exploded diagrams and reference numbers that a John Deere parts counter uses. If you want to understand how a turbocharger oil drain line routes, the factory drawing shows the exact clips and bolt lengths. Aftermarket books sometimes merge two different generations into one drawing. That’s how you end up with a bracket that doesn’t line up.

Audience Fit: Who Needs This 6620 Parts Catalog

If you’re rebuilding a 6620 combine in your own shop, or you’re a custom harvester maintaining a fleet, this catalog saves you from ordering parts twice. Home garage guys who want to restore an old 6620 will find every fastener and seal listed. The language is direct, no soft soap. Every section is labeled with the grid code, so you can navigate by the physical location on the machine. For a deep dive into diesel engine theory, see this Wikipedia article on diesel engines or read this Wikipedia article on diesel engines for background on the 466 engine family.

Frequently Asked Questions

Does this catalog include torque specifications for engine bolts?

No. This is a parts catalog, not a service manual. Torque specs are in the technical manual.

How do I find the correct part number for a hydraulic pump on an older 6620?

Start by locating the combine serial number and PIN. Then go to the hydraulic system section (grid 02B for pump and reservoir). Each grid has an exploded view with item numbers. The adjacent list gives the part number, description, and quantity. Cross-check the serial number range listed at the top of the grid. If your machine falls within a range, that part number is guaranteed correct. For example, the main hydraulic pump is shown in grid 02B13 for later models. You must verify your serial number against the break point listed on page 2 of the catalog, which notes that Titan II combines start at serial 610301. Using the wrong range will give you a pump with different mounting ears. I’ve seen that mistake cost a farmer a weekend of rework.

Can I use this catalog for a 6620 with a 653 row-crop head?

Yes. The catalog includes references to the 653 head in the front-matter notes. The head parts are in a separate catalog (PC-1558 for 200 series platforms), but the combine sections cover the feeder house and drive components that interface with the head.

Is the catalog available in formats other than PDF?

Digital access only at AutoRepairManuals. You get the full 1265 pages as a searchable PDF.

Avoid guesswork. Access the Factory Manual and get the right part numbers every time.