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LBS

Simp 9020/4040 and Allis 620/720 differences

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LBS
I thought I saw this posted before but I could not find it. What is the difference between the 9020 and the 4040? It seems I remember someone said they were exactly alike except the engines are different. I know the only difference in the engines are the carb, intake and flywheel and that may be what I was thinking. Also, are the Allis 620 and 720 direct equivelents of the Simplicity 4040 and 9020? I need to know because I need a BIG tractor/mower. Weight is more of a concern to me than HP so a 16 HP 4040 would be just fine as long as it had the weight and size of the 9020. is the AC 720 bigger than the 9020? Anyone have one of these things with a bad engine they would be willing to sell or trade for a 7790? I'm a buyer! Lawrence

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UCD
Lawrence I believe they are the exact same tractor only differance is engine Hp 16 Hp - 20 Hp Both Simplicity and Allis Chalmers Anything free is worth what you pay for it This & $1.00 might get you a small Coffee Maynard aka/UCD

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powermax_paul
Lawrence, These tractors are all built on the same frame. The early models wer the Simplicity 4040 and AC 616 which were equivalent with a 16.5 HP Onan CCKA motor. The next model series were the Simplicity 4041 and AC 620 which were built on the same frame with only minor parts differences in the transmission gearbox from the earlier series and with a more powerful 19.5 HP Onan CCKB motor. Then came the Simplicity 9020 and AC 720 which from what I can tell are identical to the 4041/620 series but with different numbers. Who knows why? The only differences in the Simplicity and AC for each series was in sheet metal. Paul

Paul Kjorlie, The Norwegian

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powermax_paul
Yes, they all had the 3 speed range in the gearbox and all used the same Sunstrand Series 15 Hydrostatic Unit. The 3pt hitch, hourmeter, rear pto, front hydraulic connections, headlights, hourmeter, etc. were options available on all years and all models. Paul

Paul Kjorlie, The Norwegian

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SmilinSam
The 4040/616 used a different clutch assembly than the later 4041/620/9020/720. When they switched to these models they changed the size of the bearings and short splined shaft, which also meant changing the pivot arm. Also changed were the tranmission driveshaft, driveshaft yokesand assorted pieces connecting the assembly to the tranmission pump. None of those parts are interchangable between the two earlier models and the four later models. The major difference between the 4040/616/4041/620 and the 9020/720 is in the front axle, spindle , and hub assemblies. On the earlier 4 they were using a large taper bearing on the inside of each front spindle and a smaller taper bearing on the outsides of each spinlde. On the later 2 they did away with the smaller bearing and used the larger bearing on both inside and outside. This meant changing the spindles and the hubs, and they also changed the cap and steering rod connectios on these newer tractors too, which meant making minor alterations to the front axle assembly. Again, thes parts are not interchangable between generations of tractors. These are just the changes I am aware of from "learning the hard way".......... Sam

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CleanBee
The early production years of the 720 were exactly the same as the 620 except for the decals. Later production years they switched the front end parts as Sam had said. I do not know exactly when they switched. Dan

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LBS
Thank you! I feel bad asking more questions than I answer But I'm so dumb I just look thru all the posts for one that I know something about and of course some one has already answered better than I could have! Anyway, I'll just keep on trying and maybe I'll learn something by the time I'm as old as most of you!

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