8070 How/Low Power Source
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=179240
Printed Date: 23 Jun 2025 at 6:22am
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: 8070 How/Low Power Source
Posted By: tthams
Subject: 8070 How/Low Power Source
Date Posted: 22 Mar 2021 at 10:59am
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I am curious if anyone knows where the power source comes from the high/low transmission switch on a 8000 series Allis. We got the transmission overhauled to the tune of $9,300. I am not going to lie, the transmission was making noises when pulling up a hill before. Now I don't even hear anything from the transmission when pulling something. Anyway the high/low wasn't working when we got it back. The shop guy said it worked for him, and thought it was a short of some kind. We tested the toggle switch over the weekend, and no power. I tried to see if the power source came from the fuse panel, the alternator, the key switch... You name it, I can't find where the green wire connects to. As you can see in the picture it goes into the wiring loom. The solenoid only has two wires going to it, which is black and white. To sum things up I tapped into the key switch to power the (high/low) toggle switch for the transmission and everything works as it should. I am just curious if anyone knows where the high/low get its power from to power the high/low solenoid. I could not find the power source. (I hope I uploaded the pictures correctly.)    |
Replies:
Posted By: Lynn Marshall
Date Posted: 22 Mar 2021 at 11:29am
| Early tractors used fuses,later tractors had circuit breakers. I believe that there's a decal on that one brown panel that shows the purpose for each fuse or breaker. Owners manual has a detailed wiring diagram in it. |
Posted By: tthams
Date Posted: 22 Mar 2021 at 11:58am
| Thanks for the reply. I'll have to check again sometime. I looked the circuit breakers over. I must have missed the sticker on the brown panel explaining each breaker. I couldn't even find one with a green wire going to it. |
Posted By: Ron(AB)
Date Posted: 22 Mar 2021 at 2:25pm
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Check the clutch pedal safety start switch. I believe it has to work before the hi/low switch will work. It could be stuck...need of replacement, etc. ------------- 405, 7000, 7050, 8050, 8070, L3, 2300 & 2600 disk |
Posted By: tthams
Date Posted: 22 Mar 2021 at 3:17pm
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That does make sense. Prior to the transmission going bad there would be days where the transmission would shift great, and then later in the day it would not want to shift for awhile, and then it would start to work again. Maybe a failing sensor switch? I will have to check and see if I can start the tractor now without pressing in the clutch. Stepping in the clutch has always been the normal for me.
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Posted By: Lynn Marshall
Date Posted: 22 Mar 2021 at 10:14pm
| There is a clutch safety start switch in that area, but it doesn't have anything to do with the power director part. There is another switch in that same area that is used as a kick down to the low side of the power director every time that the clutch is depressed. That is so you always start the load in the low side and then you can always shift up. The low side has more plates and is made for inching a load also. I believe that those switches are identical. If that switch was stuck, you wouldn't be able to shift to the high side. When you look at it again, I think you'll see which switch does what. There's also a relay there by the fuse panel that is for the power director. It could be bad. |
Posted By: tthams
Date Posted: 23 Mar 2021 at 5:51am
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That makes perfect sense. Thanks everyone for helping me figure this out, and look at it from a different approach. I will be calling AGCO today to pick up parts. |