D-18 and then D-19 development
Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=209437
Printed Date: 21 Dec 2025 at 4:14pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: D-18 and then D-19 development
Posted By: DrAllis
Subject: D-18 and then D-19 development
Date Posted: 21 Dec 2025 at 8:09am
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Looking back, this is how I think things probably went down from 1958 until late 1961 for the AC tractor division. It was determined that a tractor larger than the D-17 was needed. How many $$$$$ that are allotted to the design engineers has a direct effect on what you'll get. A clear direction from the Sales Dept and upper/upper management on what they want is also extremely important. So, the D-18 proto, from the instrument panel forward to the front axle began as a D-17 diesel. Nothing more. Nothing less. The first change was to use the existing 6-cylinder B-series gasoline engine at 262 cubes. The diesel engine, as I understand it, got bulked up on the bore/stroke combo to around 290 cubes, naturally aspirated. Both engines were then rated at 2,000 RPM. This placed the HP output at far less than they eventually wound up with. So, everything inside the torque tube, including the hydraulic pumps basic design, was pretty much the same as the D-17 tractor. Little $$$ spent so far. The transmission, ring and pinion and differential were also the same as the D-17, just inside a new housing. Again, very little $$$$ spent. The rear end housing/casting was indeed all new, and housed the new inboard final drives, so a bar type rear axle could be used. They spent some $$$$ on that, and for the most part, I have no issues with what they did. I've never had any failures of the new design final drives or axles/bearings, etc. The drawbar area was also strengthened and was pretty good. A 3-point hitch wasn't ready when the tractor was first released and that was too bad. Their 3-point was finally as good as anyone else's at the time, just not ready from the beginning. That, is how I feel the D-18 tractor came to be. The hydraulics still weren't "live" or more than 6 GPM's in flow. They did however have a new tripe spool hydraulic valve. And, the HP levels were found to be lower than sales demand was going to be. The 100 HP D-21 was clearly a different and separate project and may have been started the day after the John Deere 4010 was shown to their dealers in August of 1960.
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Replies:
Posted By: cwhit
Date Posted: 21 Dec 2025 at 11:08am
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Doc, I spent a lot of hours ona D-19 and my only question would be , why were the hyd levers on the left, when all other D series wear on the right?
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Posted By: DrAllis
Date Posted: 21 Dec 2025 at 11:13am
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Series 4 D-17 was on the right. D-21 was also on the right. They were "live" hydraulic pumps. All the other D-series valves to the left of the seat (optional except for D-19) had to be on the left, so you could release the hand clutch to stop tractor movement with your right hand and then operate the hydraulic levers with your left.
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Posted By: Don(MI)
Date Posted: 21 Dec 2025 at 11:20am
That makes sense doc...
Even on the W series and early D series Hyd. Controls were on the LH side, I was thinking back then as the Allis Implements were LH side also, you could see what you were controlling while operating.
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Galatians 5:22-24
"I got a pig at home in a pen and corn to feed him on, All I need is a pretty little girl to feed him when I'm gone!"
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