Farm Equipment - Advice on Powershift Troubles

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Advice on Powershift Troubles

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=181701
Printed Date: 17 Jul 2025 at 11:18pm
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Topic: Advice on Powershift Troubles

Posted By: tthams
Subject: Advice on Powershift Troubles
Date Posted: 11 Jul 2021 at 7:33am

I was wondering if I could get a second opinion. I recently had a powershift transmission rebuilt to the cost of almost $11,000 in a 7060.

I used it yesterday and while driving down a gravel road not pulling anything, and I was in 6th gear high side. After around 20 minutes of driving the RPMs began to decrease rapidly with no warning. I stepped in the clutch otherwise the engine would have killed itself.

I called the guy that rebuilt the transmission, and he told me to try it in first gear. Nothing, the rpms began to bog down instantly. He told me to shift to low side and try moving the tractor in 1st gear. It worked and the tractor began to move.

I then shifted into high side, and slowly worked up the gears. The tractor seems to loose RPMs easier in 6th gear than normal, and I could hear it in the engine also, so I drove it home the last 2 miles in 5th gear. By the time I parked it, I could smell that the transmission what hot. Like a burnt smell.

The guy that is well known for his quality work, is coming to the farm. He thinks something might of happened to the valve body. He was wondering if a 3rd clutch disc was engaging. The transmission has less than 5 hours on a rebuild.

I am not very well versed on how a powershift and how the valve body operates. Could there be something going on in the transmission, or would adjustments in the valve body fix the issue?

Thanks!

Replies:

Posted By: Lynn Marshall
Date Posted: 11 Jul 2021 at 8:21am

There may be a problem in the valve body that would cause a third clutch pack to be engaged. But,if that third pack was slipped for very long, it's probably warped and ruined. No exactly what you wanted to hear.

Posted By: DrAllis
Date Posted: 11 Jul 2021 at 8:24am

The transmission clutches only do what the valve body tells them to do. There can only be TWO clutches engaged at a time. Three (because of a stuck valve) will cause BIG troubles.

Posted By: DrAllis
Date Posted: 11 Jul 2021 at 8:34am

I will relay a very bad repair that I encountered 30+ yrs ago (by someone else), and it was also related to 6th gear operation. There are three cast iron sealing rings inside of the C1 and C2 (reverse) clutch pack hub which is at the rear of the tranny. If these three sealing rings have not been replaced with new (takes more labor to do so) and checked for proper "squeeze" when installed, the reverse C2 clutch may be getting a small amount of oil delivered to it when it shouldn't be. The high RPM's seem to allow the dribble of oil into that C2 clutch to lightly apply it. Very difficult to catch on a clutch pressure gauge and the conditions have to be just right (hot oil and extended high RPM's in 6th gear) to cause this to happen. Ever since that problem child, I usually increased drain orifice size on the C2 clutch. New wave springs in C2 is also a good idea. So, if the C2 reverse clutch is smoked, either the C2 valve was stuck or this oil leakage scenario is the cause.

Posted By: tthams
Date Posted: 11 Jul 2021 at 10:44am

The guy says he stands behind his work. So if it happened once, it most likely will happen again under same conditions.

Would you recommend tearing the transmission apart again then to get to those seals? Are there things to look for after he works on the valve body to look for damage to the transmission?

The guy is coming this week to look at the valve body. But I agree, I think something is toast in the transmission.

Posted By: DrAllis
Date Posted: 11 Jul 2021 at 8:01pm

If the reverse C2 clutch is smoked, I'd be sure to ask him if he changed out the three 70267717 hook-type sealing rings on the rear clutch support. it is something that could have been skipped. What was the exact nature of your transmissions failure to begin with ???????

Posted By: Lynn Marshall
Date Posted: 11 Jul 2021 at 8:13pm

Once you get the valve body off, you may be able to see a clutch pack that is discolored or blackened from the heat. However, not all of the packs are visible through the valve body hole.

Posted By: tthams
Date Posted: 11 Jul 2021 at 8:17pm

I am looking at the bill, and I can gladly private message you Dr. Allis and send you pic of bill if you would like. It lists everything he has done. I don't see 70267717. But I see 70267713 that is the closest to the number which lists it as seals.

Here is a link to the original post I from last November. It lists the original issues I was seeing.

https://www.allischalmers.com/forum/7060-power-shift-has-me-puzzled_topic175626.html" rel="nofollow - https://www.allischalmers.com/forum/7060-power-shift-has-me-puzzled_topic175626.html

Posted By: DrAllis
Date Posted: 11 Jul 2021 at 8:27pm

The potential problem I have proposed would only happen in 5th gear, not 6th. My bad. Just been toooo many years ago to remember for sure. It could happen in 4th and 3rd and second as well, but like I said, it is RPM/centrifugal force related and with hot operating temp oil and for extended run time at full throttle.

Posted By: tbran
Date Posted: 11 Jul 2021 at 8:27pm

We are beginning to see metal fatigue show up. We rebuilt a high hour 7060 and it failed after 20 hours - the C2 clutch pack fractured where the lip seal rode... dumping oil pressure .. another 8070 had the machined area between the seal rings break off and float... probably see more of this as time goes by... we will do much more and closer inspections especially if there has been shock type failures..

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

Posted By: MACK
Date Posted: 11 Jul 2021 at 8:30pm

Make sure he sucked all the old oil out of transmission when it was rebuilt. There is a area under dip stick that don't drain. Either pump it out or suck it out (about 2 gal). Crud from original failure could have got into valve causing 2nd failure.

If it is not gone through again, there most likely going to be a 3rd failure. When a 3rd clutch engages parts go to &%$$ in a hurry. MACK

Posted By: tthams
Date Posted: 11 Jul 2021 at 8:51pm

Thanks again for the input everyone. You are sharing what I was fearing about tearing it apart again.

I love Allis, and grew up with Allis. I always wanted a powershift on the farm. My dad would never budge off of power director transmission. Maybe he knew something I didn't. Power shift transmission currently seem to be more problems than they are worth :(

The guy is coming this week to look the tractor over, but I think the tractor has to be torn apart again. I bought the tractor last September in 2020, and have maybe 20 hours on it. With more down time coming again. It will be on his dime this time.

I will post what he says. He knew my Dad very well, and he is well know in the area for quality work. He use to work at Robinson Implement (Agco) fixing things, so I trust him.

To address the issues of dirty oil in the bottom on the tranny, I personally drained the oil from the plate at the bottom of the transmission housing, and replaced the filter. Wouldn't he see the dirty oil during the rebuild that you are talking about?

Posted By: DrAllis
Date Posted: 11 Jul 2021 at 9:56pm

The dirty oil left behind is inside the range transmission. Probably 2 to 3 quarts ?? but if it's dirty and filled with iron filings, it gets washed right into the new oil and new transmission parts.

Posted By: tthams
Date Posted: 14 Jul 2021 at 8:46pm

I spoke with the guy that did the transmission rebuild today. He is going to warranty his work. The the tractor will be delivered to him on Saturday.