AC 8050 PD hard shift
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=159990
Printed Date: 19 Oct 2025 at 6:02pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: AC 8050 PD hard shift
Posted By: mechanicmarty
Subject: AC 8050 PD hard shift
Date Posted: 13 Apr 2019 at 10:28pm
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Good day, hope you guys can help me. My dad bought an 8050 with the PD transmission, he bought it knowing the reverse gear did not work. The tractor was shipped to his shop where my brother and I pulled the transmission top plate and found the reverse gear, idler reverse gear and 5th gear were damaged. We removed the cab, split the the tractor between the engine and transmission. We removed the transmission and I rebuilt it. I also disassembled the PD to inspect for damage but found none. We put everything back together, everything works good except when selecting a gear it’s grinds a bit. When I try to pull it out of gear it’s hard, almost like the clutch isn’t fully disengaging. I checked the clutch linkage adjustments according to the service manual and also the transmission brake pressure which are both ok. I have yet to check low and high clutch pressures. Any ideas? Thanks for the info
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Replies:
Posted By: MACK
Date Posted: 14 Apr 2019 at 8:15am
Let up a little on clutch pedal to get out of brake poisons will help shifting.
Give a little time for gears to stop turning before shifting into gear. MACK
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Posted By: mechanicmarty
Date Posted: 14 Apr 2019 at 9:45am
Thanks for the info MACK, I tried driving the tractor this morning the way you suggested. It doesn’t seem to matter how long I wait for the transmission to slow down, it still grinds when put in gear. I have to shut the tractor off to get out of gear. Also when in the low range and lower gears the tractor creeps ahead unless I hit the brakes. I’ve got hoses coming in tomorrow to hookup to the test ports for the power director low and high oil pressure to see if there is still pressure when I push the clutch. The service manual suggested this symptom could be caused by: clutch linkage adjustments
Warped clutch disks
Plugged drain orifice on high clutch housing.
I’ll test it tomorrow or Tuesday and post the results.
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Posted By: Lynn Marshall
Date Posted: 14 Apr 2019 at 10:56am
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It's very easy for a clutch disc to get out of place when reassembling the power director. This would act the way you are describing.
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Posted By: mechanicmarty
Date Posted: 14 Apr 2019 at 11:55am
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I’ll check the pressures first for piece of mind, if they are good then I’ll split the tractor and pull out the power director. Thanks for the info
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Posted By: DrAllis
Date Posted: 14 Apr 2019 at 11:59am
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Removing the sump cover under the clutch would allow you to give it a visual to see if the spacing is equal between all the discs/plates before a split.
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Posted By: mechanicmarty
Date Posted: 14 Apr 2019 at 12:11pm
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That’s awesome! From what I can see in the parts description the high clutch orifice is also accessible from the sump cover. The reason I’m hell bent on the clutches still having oil pressure when the clutch pedal is pushed is because the damage done to the reverse gears we replaced looks like they kept grinding when shifted. Thanks
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Posted By: mechanicmarty
Date Posted: 23 Apr 2019 at 4:19pm
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Thank you MACK, Lynn Marshall and Dr Allis, for your info. I test low clutch pressures and found it went to 0psi when the clutch pedal is pressed. I readjusted the clutch linkage and took it for a test drive. It drives much better, the gear shift cable needs to be replaced. But other than that it shifts fine when the clutch is used properly. Thanks again for the info.
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Posted By: DougG
Date Posted: 23 Apr 2019 at 6:31pm
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Glad you got it figured out , you seem very mechanical inclined! Good work!
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