Seasonal disconnect?
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=210656
Printed Date: 18 Sep 2026 at 9:27am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Seasonal disconnect?
Posted By: whatscooking
Subject: Seasonal disconnect?
Date Posted: 06 Apr 2026 at 5:51pm
| What does it take to seal that shaft where it goes into the side of the tractor? |
Replies:
Posted By: SteveM C/IL
Date Posted: 06 Apr 2026 at 6:09pm
| what tractor? |
Posted By: AC720Man
Date Posted: 06 Apr 2026 at 6:18pm
|
I’m guessing 6060,6070,6080? ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |
Posted By: DrAllis
Date Posted: 06 Apr 2026 at 6:45pm
| The D-21 PTO seasonal disconnect shaft oil seal is an O-ring (certain size and hardness) that fits in a groove on the levers shaft. To remove the shaft, one must remove a roll pin (or maybe a solid groove pin) from the inside of the four-speed transmission. It's normally a hammer and punch kind of removal. I've never done one in chassis before and don't know how much room there is to work in that area after removing the platform and shift cover from the top of the transmission. I'm pretty sure if the four-speed was split from the rear end and rolled ahead 3 or 4 feet, there would be a way to drive out that pin from the rear. If there's enough room from above, I'm sure I could figure out a way to remove the pin from the top, instead of a split. Anyway one goes about it, easy it will not be. |
Posted By: whatscooking
Date Posted: 06 Apr 2026 at 6:51pm
If it's split for a clutch does that help? |
DrAllis wrote:Posted By: DrAllis
Date Posted: 06 Apr 2026 at 6:56pm
| That would require lifting the complete control module off the top of the bell housing and splitting it from the front of the four-speed transmission. Probably could be done that way but a lot of work. A rear split is easier. Is there a clutch problem too ?? |
Posted By: whatscooking
Date Posted: 06 Apr 2026 at 6:59pm
| Transmission fluid out the hole. |
Posted By: whatscooking
Date Posted: 12 Apr 2026 at 3:36am
| There has to be many of these D21s leaking? |
Posted By: DrAllis
Date Posted: 12 Apr 2026 at 7:19am
| Built in 1963-69. So 60 years on the original O-ring?? Yup, unless someone has replaced it before, it probably leaks. So, with the 4-speed transmission cover removed, one could take a long pry bar and get it up against the internal shifter and force it outwards (compressing the detent spring or just remove the detent spring from the outside first) as far as it will go and hold it there. I would then take my Makita angle grinder with a thin cutting disc and carefully cut off the end of the shifter shaft, dropping the long lever on the ground with a very short stub still welded in it. Or grind the weld thin enough to break the long lever free from the shaft and then cut the shaft off making it a squared off shaft end. I have a mag(netic) drill, so my next step would be to drill a hole in the end of that shifter shaft 5/16" or 3/8" diameter and tap NC threads in it. Lots of air and brake kleen to dry the area free of any residual oil (transmission drained). Push the shaft inwards as far as it will now go. Place a thin thickness Oring into the shafts hole with an O.D. that fits the hole and stays put. Fill the hole with black oil resistant RTV. Procure or fabricate a thick flat washer to now bolt up to the end of that shaft, drawing the shaft up against the thick flat washer and placing the RTV and that Oring under a squish. Let it cure for a couple of days. Before the final squeeze, use that long pry bar to place the shifter collar engaged or disengaged, as you desire, before tightening the bolt. The flat washer can just be a square flat iron of 1/4" thick (minimum) steel with a proper size hole drilled in it. It must be larger than the hole in the transmission case for the RTV to be fully mooshed out. |
Posted By: A-C_220
Date Posted: 12 Apr 2026 at 12:27pm
| I did it a couple years ago. Take the transmission shift cover off and drive the pin out and pull the lever out |
Posted By: DrAllis
Date Posted: 12 Apr 2026 at 1:37pm
| So, there is room to do it without splitting the tractor, yes ?? |
Posted By: whatscooking
Date Posted: 28 Jun 2026 at 10:25am
| Update. Tractor is split becuase the transmission seal wasn't replaced when the clutch was replaced and leaked horribly, clutch and flywheel are perfect. Had trans top off but would been a real challenge. Took bell housing off which allowed axcess and took bellhousing to a machine shop to bush ft end pivot hole. Comming together. |
Posted By: DougG
Date Posted: 28 Jun 2026 at 2:00pm
| Must have missed something- what are you working on? Only disconect I know of is on a 6000 series |
Posted By: whatscooking
Date Posted: 28 Jun 2026 at 7:41pm
| D21, lever by the brake pedal that disconnects the PTO driveline. |
Posted By: Lars(wi)
Date Posted: 29 Jun 2026 at 12:24pm
|
As I am admittedly totally ignorant on this, what is the purpose of ‘seasonal disconnect’? ------------- I tried to follow the science, but it was not there. I then followed the money, and that’s where I found the science. |
Posted By: whatscooking
Date Posted: 29 Jun 2026 at 12:57pm
| ALLIS-CHALMERS designed the D21 so you can disconnect the hand lever clutch and related drive from the transmission. Wear and tear, horsepower gain and noise i only suppose is the reason. |
Posted By: AC720Man
Date Posted: 29 Jun 2026 at 10:20pm
|
As you can see from my early post I thought this was a 6000 series tractor that was in question. Never heard it referred to a seasonal disconnect on a D21, but then again I have never owned one. ------------- 1968 B-208, 1976 720 (2 of them)Danco brush hog, single bottom plow,52" snow thrower, belly mower,rear tine tiller, rear blade, front blade, 57"sickle bar,1983 917 hydro, 1968 7hp sno-bee, 1968 190XTD |