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8070 hydrauic pump drive

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=211923
Printed Date: 17 Sep 2026 at 5:47pm
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Topic: 8070 hydrauic pump drive
Posted By: 8070nc
Subject: 8070 hydrauic pump drive
Date Posted: 08 Aug 2026 at 7:16am
Ive got a 8070 that stopped all power outputs all if a sudden. No noise no shudder just stopped. Motor runs but nothing else works. I immediately think torque limiter but in my sleep i think it might be a stripped hydraulic pump drive. The symptoms would be the same i think. How would you tell the difference?

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor



Replies:
Posted By: tbran
Date Posted: 08 Aug 2026 at 5:28pm
IF the pump drive is sheared, there will still be some friction on the clutches and if you rev it up and leave the high low in neutral - then it will grind when trying to shift into high and low.  A scope up the hole below the flywheel ? 

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When told "it's not the money,it's the principle", remember, it's always the money..


Posted By: DrAllis
Date Posted: 08 Aug 2026 at 6:42pm
I have never ever seen a pump drive fail. I have seen dozens of torque limiters do just what yours has done. If you really want to check, remove the top link bracket to the three point hitch. Remove the soft plug behind it. Thread a short 1/2" bolt into the upper PTO shaft and tighten it. If you can continue turning that bolt in a clockwise circle, the torque limiter has eaten its pigs.


Posted By: Lynn Marshall
Date Posted: 08 Aug 2026 at 6:45pm
I've personally never seen a hydraulic pump drive line failure in over 50 years experience on the 7000,8000 series. Always the torque limiter for me. If the ring gear bolts back out, like some were known to do, it raises hell with the rear shaft in the housing. They still never lost hydraulics when that happened.


Posted By: 8070nc
Date Posted: 08 Aug 2026 at 6:55pm
I had thought about the scope in the bell housing. I didnt know about what you said about the transmission. Everything just stopped all if a sudden with no noise. First thought is if course torque limiter but i woke up in the middle of the night with the thought of the hydraulic pump drive. I was just running a nitrogen applicator so there was hardly no load. Ive got enough information now to figure it out
Thank you

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1984 80780
1957 D14
DES 300 with 25000 engine
616 tractor



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