Farm Equipment - D12 series 3 snap coupler/3 point lift

D12 series 3 snap coupler/3 point lift

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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=210079
Printed Date: 17 Feb 2026 at 10:22pm
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Topic: D12 series 3 snap coupler/3 point lift

Posted By: John R Price
Subject: D12 series 3 snap coupler/3 point lift
Date Posted: 16 Feb 2026 at 12:32pm

It's been about 20 years since I have posted anything here. I don't know if protocols have changed and I can't get the search box to work for me to possibly answer my own question. If I am acting out of order, please forgive me.

I recently picked up a D12 series 3 with the snap coupler hitch. I'm don't know much about the tractor's former maintenance, so I'm going through it. The rear lift is very slow to lift and wants to give up when the brush hog begins to come off the ground. I have checked the oil and its full and seems clean. I find no leaks. Looking at the oil, I believe it may be gear oil as its fairly thick.

Q#1, If so, would others believe the oil is too think for the pump to pick up the oil and pump it? I know 10w30 is what the entire tractor is recommended to use.

Q#2, what if the reference # for the hydraulic filter near the hydraulic pump?

Q#3, what brand or location does anyone recommend to find this filter?

I'm open to any recommendations/suggestions/assistance. I'd really like to hope my problem can be drained out and the solution poured back in. I know, that's likely a fairytail.

Thanks to everyone for their assistance. JP

Replies:

Posted By: Macon Rounds
Date Posted: 16 Feb 2026 at 1:21pm

Never saw a series III with snap coupler ...

That would be interesting to see...

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The Allis "D" Series Tractors, Gravely Walk behind Tractors, Cowboy Action Shooting !!!!!!! And Checkmate

Posted By: John R Price
Date Posted: 16 Feb 2026 at 2:57pm

I don't know what to tell you about the snap coupler vs 3 point on a series 3, but this tractor is a put together. I know the engine is not the original engine mated to the high/low transmission. The engine is a 1963 per the serial number. I know the high/low didn't arrive in 1963, they came into the line up in 1965 or 66. The engine has a different shade of orange and the rest of the tractor has two coats of poorly done orange paint. There are tell tale signs of this tractor being damaged at some point and some cobbled up fixes. Any correct information on production dates are welcome. And if there is a way to identify the transmission manufacture date, that would help too.

Thank you! JP

Posted By: DiyDave
Date Posted: 16 Feb 2026 at 3:17pm

Dors it have the Hyd pump in back, on top of PTO?

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Posted By: steve(ill)
Date Posted: 16 Feb 2026 at 3:32pm

dont know what size cylinder you have or what you lift is rated at.. but you should NEVER have gear oil in the system.. I would drain and fill with a 20wt hydraulic oil, hytrans, universal tractor fluid, or your 10w 30 if you wish.. anything that is thinner and in the 20wt range.... then see what happens.

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Like them all, but love the "B"s.

Posted By: John R Price
Date Posted: 16 Feb 2026 at 8:08pm

Yes, the pump is over top of the PTO.

Posted By: John R Price
Date Posted: 16 Feb 2026 at 8:17pm

Changing the oil to a known proper hydraulic and the filter is my leading idea. But I'm going to study on this a bit more, and I'd like to hear of other's solutions.

Posted By: steve(ill)
Date Posted: 16 Feb 2026 at 8:47pm

is there an exposed line where you could put a TEE and measure the pressure in the system ? ......... that would narrow down the problem.

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Like them all, but love the "B"s.

Posted By: DrAllis
Date Posted: 16 Feb 2026 at 9:00pm

Just plug a 3000 psi gauge in the remote outlet and dead head a remote lever at full throttle.

Posted By: PaulB
Date Posted: 17 Feb 2026 at 5:08pm

All series of the D10/12 tractors could have had a SnapCoupler from the factory. Although if the tractor you have looks to be a "Johnny Cash" version it is highly probably the the lift system could have been changed to SnapCoupler from 3pt as the D10/12 3pt hitches were such pispoor design that even minor abuse would destroy them.

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