Difference between a JD6600 and a 6620

I have been farming for 20 yrs with 6600 I have come across a 6620 with low hrs.Curious what the difference is between them is,I would like to keep one of my 6600 for parts .I know the 6620 has a swing out auger and a different cab are the internals the same?

The straw walkers are longer. The 20 series did away with the bicycle chain cylinder adjustment. I think a lot of the separator is the same other then the walkers if you are comparing it to a yellow cab Titan 6620. I know my neighbor robbed a few parts off our 7700 to get his 6620 going. After he was done he brought them back.

The largest differences between the 6600 and 6620 Titan (early with yellow cab tops) was the cab improvements, larger grain tank, the added 2 foot step on the walkers, the turret style discharge auger, a modest bump in horsepower, a step up to the 466 diesel engine, and the cylinder drive and feeder house drive were changed to the "posi-torque" drive set up. I suspect the straw chopper may have been beefed up, too. The internals of the machine were not significantly changed, as the cylinder and concave were all the same size as the 6600, as was the cleaning shoe. Unless one was operating in conditions where some added horsepower was needed, I have never thought one would see any significant gain in capacity between a 6600 and a 6620. It was with the Titan II series, with the green cab top, where the cleaning shoe was lengthened, as well as sped up, where a measurable gain in capacity could be expected. We had a 7700, but never upgraded to a Titan or Titan II to compare. Again, as I recall from my reading up on the machines when they were new, there really wasn't anything changed internally to bring an increase in capacity. I remember going to a farmer meeting in preparation for the upcoming fall in the early 1980's, and being told of all the changes of the machine itself, between the older 6600/7700 and the 6602/7720 Titans. I approached the "block man" from Deere who had presented and asked him if any of these changes could truly result in an increase in overall capacity. His response was a "corporate response" and I continued to press the issue. He finally admitted the only substantial changes "internally" in the machine was the added 2 foot step to the straw walkers, and it would likely only be in conditions where power was truly needed, a modest increase in capacity may be experienced.

I think the capacity differences might have been more noticeable in small grains. The extra length on the walkers did help in those crops. There is a reason why Massey kept lengthening the walkers on their combines after JD introduced the 00 series and again when JD introduced the 20 series. And JD did make the concave slightly bigger in the 20 series by adding one more bar and they advertised the beater grate area had been increased 51% over the old 00 series grate. The bigger shoe on the T2 I thought was more for the corn belt because we didn't see any difference between our Titan 8820 and T2 8820. The grain would almost start going out the walkers before the shoe. Corn might be different though. All it did for us was the shoe flew apart on the 8820 T2. After we go it back together we put the regular Titan sprocket on it to slow the shoe down and never had problems after that.

So the straw walkers from the 6600 will not go into a 6620?

Longer walkers are significant in small grains where walker loss is an issue. Would definitely prefer a 20 around here for that reason.

(quoted from post at 13:02:26 12/20/17) I think the capacity differences might have been more noticeable in small grains. The extra length on the walkers did help in those crops. There is a reason why Massey kept lengthening the walkers on their combines after JD introduced the 00 series and again when JD introduced the 20 series. And JD did make the concave slightly bigger in the 20 series by adding one more bar and they advertised the beater grate area had been increased 51% over the old 00 series grate. The bigger shoe on the T2 I thought was more for the corn belt because we didn't see any difference between our Titan 8820 and T2 8820. The grain would almost start going out the walkers before the shoe. Corn might be different though. All it did for us was the shoe flew apart on the 8820 T2. After we go it back together we put the regular Titan sprocket on it to slow the shoe down and never had problems after that.

Click to expand...

The longer straw walkers were introduced for European market on black interior 700 series for 1976.
As usual, JD did copy MF as far as treshing systems goes. Still, the Deere 20 series carries the MF510 drives layout that is overly complicated versus the simple layout of the MF760-860.
Only thing Deere did better than MF on 20 series is the rubber mounted cab, and the trumpet style final drives on 8820 so you can dual them up.