Farm Equipment - AC 8550 Transmission HELP

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AC 8550 Transmission HELP

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=12247
Printed Date: 01 Feb 2025 at 4:55pm
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Topic: AC 8550 Transmission HELP

Posted By: bkrapp
Subject: AC 8550 Transmission HELP
Date Posted: 10 May 2010 at 9:56am

Hi there, we recently bought an 81 AC 8550 with around 7000 hours. The tractor runs and worked perfectly for about 30 hours of field work this spring for us. We were rolling beans yesterday and just as we kicked the foot button on the floor into high after turning a corner it started grinding very badly and the tractor stopped moving. It makes a high grinding sound kind of like when a starter is grinding on the ring gear but louder. It doesn't make the sound out of gear, only when the tractor is put into gear. I am wondering if any of our have a diagram of the parts you feel this would be or if you have some knowledge of this and if there are weak points in these tractors. looking in my service manual, it looks like there are some couplers in between the drop box and the transmission. If anyone could elaborate on this I would really appreciate it. My manual is a copy and you can't see the pictures worth a hoot. Also if anyone would have or know where parts for this would be would be great. I thank all in advance. Thanks

Replies:

Posted By: 7060
Date Posted: 10 May 2010 at 11:31am

You can go to http://www.agcopartsbooks.com - www.agcopartsbooks.com and look at the book online. I think the 8550 still had the same transmission as the 7000 series tractors and same drop box as 7580 but they had different gearing. Does it move in any combination of gears or ranges, maybe even in neutral. Does it want to die when the clutch is let out? How was the oil level in the transmission?

Posted By: DrAllis
Date Posted: 10 May 2010 at 11:45am

8550/4W305 are a totally different tranny and parts might be hard to come by. I do know they are good at drop box failures of some kind....may be the issue here/?

Posted By: bkrapp
Date Posted: 10 May 2010 at 11:50am

No it doesn't move in any combination of gears. It doesn't wnat to die, it just grinds like something stripped out. The oil level was good. Thank you for the info and any help you can give me.

Blake

Posted By: DrAllis
Date Posted: 10 May 2010 at 12:03pm

Shift the 5 speed into any gear and leave the range lever in park.....see what the sound is like then with the clutch pedal up.

Posted By: Cb NwO
Date Posted: 03 Jun 2010 at 12:22pm

Where did you get this 8550 from?

Posted By: robo123
Date Posted: 03 Jun 2010 at 2:18pm

Sounds to me like maybe you striped the splines out of the middle of the Power Director clutch hub.

Posted By: Matt MN
Date Posted: 07 Jun 2010 at 11:33am

Here is a posibility for some parts.

http://www.worthingtonagparts.com/Low/salvage/ImageView.aspx?from=TearDown.Aspx&Type=&Make=&Model=&txtType=1&PartsNo=&PurchNo=03-11F-0105&sString=Latest+Equipment+Dismantled - 8550 Parts tractor

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