Farm Equipment - AC 7000 Power Shift Noise

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AC 7000 Power Shift Noise

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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=174612
Printed Date: 01 Apr 2026 at 7:47am
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Topic: AC 7000 Power Shift Noise

Posted By: Grave
Subject: AC 7000 Power Shift Noise
Date Posted: 22 Sep 2020 at 7:32pm

Have a 7000 Black belly, S/N 8254 the issue I am trying to address is that when we shift from 1-2-3-2-1 there is a groan noise, Dad doesn't believe that this noise was around before. It typically lasts for a second or two and it seems to stop when, i assume is the valve has either returned or advanced, i know there are 3 valves one for each stage. When the tractor heats up, sometimes the noise won't go away unless we wiggle the shifter or tap the clutch(assuming that this is doing the same thing as the shift due to the clutch returns the power shift to the previous stage). We recently changed the hydraulic intake hose and replaced the oil with Prematran 821XL semi synthetic and replaced the filter.

My questions are, is that noise normal? If yes, than why would the noise be prolonged as the tractor heats up?

If no, best approach to fixing?

My plan is to -check supply pressure on test port, believe 210-230 psi is range.

-check lube pressure

-check both relief valves

Also is the permatran 821XL semi synthetic the best oil? Don't think they had semi synthetic bad in the day

Replies:

Posted By: MACK
Date Posted: 22 Sep 2020 at 8:47pm

most all have some noise when shifting. MACK

Posted By: Ron(AB)
Date Posted: 22 Sep 2020 at 9:07pm

Some ideas...

1.    The power shift cable may need to be adjusted.   On the valve itself.

2.   The cab mounts may have squished lowering the linkage in the cab causing it to be out of adjustment in the cab.

3.   Have you cleaned the intake screen in the belly of the tractor?

4.   Any air leaks into the system?

I would check these first.

Posted By: Grave
Date Posted: 22 Sep 2020 at 9:22pm

1. Power Shift cable good, the clevis is free when in the detent position

2. see above

3. Assuming you mean the hydraulic intake screen in the pan where the filter is located, yes

4. That a good question and i don't know how to verify other than possible bubbles on he dipstick. There are hardly any leaks of oil on her, so i going to say no. This tractor is very well keep. We are high on maintenance.

Thank you for replies

Posted By: DrAllis
Date Posted: 23 Sep 2020 at 8:25am

Does it make the same noise when you have the PTO engaged and then do your upshifting/downshifting ?? If it shifts cleanly and crisply and doesn't show any signs of slippage when pulling a load and shifting under load, I'm not sure I'd lose any sleep over it.

Posted By: Grave
Date Posted: 23 Sep 2020 at 8:39am

Yes same noise with PTO engaged, we spray with this tractor.

Also there doesn't seem to be any reduction in power or speed, no noticeable lag. Shifts as crisply as we let it, we try and feather it into gear for smooth transition.

The fact that when it gets hot and we shift, the groan that happens during shifting doesn't always stop is the main concern. I understand that it may not be a big issue, but dad won't let it go. We will have to look into it.

appreciate replies

Posted By: DrAllis
Date Posted: 23 Sep 2020 at 8:53am

You want to spend $$$ and not waste it ?? replace the front cab mounts. I am sure they are shot. If the noise goes away, wonderful. If it doesn't, move on.