Production years
1979-1988
John Deere combine ยท 1979-1988
John Deere 6620 Combine
The John Deere 6620 is a late-era conventional walker combine built for medium-size grain and row-crop farms. It is remembered as a durable, straightforward six-row-class machine with a cylinder-and-walker threshing system.
Threshing system
Conventional cylinder and straw walkers
Engine
John Deere 466 cu in six-cylinder diesel, 125 hp standard; 145 hp turbo option
Grain tank capacity
166 bu
John Deere 6620 specifications
| Production years | 1979-1988 |
|---|---|
| Threshing system | Conventional cylinder and straw walkers |
| Engine | John Deere 466 cu in six-cylinder diesel, 125 hp standard; 145 hp turbo option |
| Grain tank capacity | 166 bu |
| Header compatibility | 13-24 ft grain platforms; 4- or 6-row corn heads |
| Weight | Approx. 18,250 lb |
| Cylinder | 22 in wide by 44 in diameter |
| Separator | Walker-type separator |
What the 6620 is used for
The 6620 was designed for corn, soybeans, wheat, and small grains on farms that needed a dependable self-propelled combine but did not require the capacity of Deere's larger 7720 or 8820. The conventional system is also appealing where retaining longer straw is important.
Today, it is commonly used by smaller farms, specialty growers, and owners harvesting limited acres. It is valued for mechanical simplicity, but realistic acreage expectations and a dependable source of parts are essential.
Why the John Deere 6620 stands out
The 6620 is notable as one of Deere's enduring conventional combines: a capable 125 hp machine with a 166-bushel tank and support for up to six-row corn heads. Its uncomplicated mechanical layout and broad familiarity among longtime Deere owners make sound examples attractive, especially for smaller operations.
Buying a used John Deere 6620
Check cylinder bars, concaves, walker crank and bearings, shoe bushings, sieves, feederhouse chain and floor, grain-elevator boot, unloading auger, belts, and hydrostatic or gear-drive condition. Rust in the grain shoe and elevator areas can be costly, so do not rely on an hour meter alone; confirm the configuration and specifications with TractorData.com and manufacturer records.
John Deere 6620 frequently asked questions
How much horsepower does a John Deere 6620 combine have?
The standard diesel is commonly listed at 125 hp, with a 145 hp turbocharged option.
How large is the John Deere 6620 grain tank?
Its commonly cited grain tank capacity is 166 bushels.
Can a 6620 run a six-row corn head?
Yes. The 6620 was offered for four- or six-row corn heads, subject to the machine's configuration and field conditions.
Specifications are commonly cited figures for general reference; exact figures vary by year and serial number, so confirm against TractorData.com and the machine's records. Values and prices of used combines vary by condition, hours, and region. Page updated Aug 4, 2026.