7020 jumping out of high range
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=145354
Printed Date: 05 Apr 2026 at 1:43pm
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Topic: 7020 jumping out of high range
Posted By: 7060
Subject: 7020 jumping out of high range
Date Posted: 11 Dec 2017 at 5:13pm
| I already made a post before about this, but couldn't find it. I have a 7020 that jumps out of high range going down hills. I took the floor and console side out tonight thinking and hoping it was out of adjustment, but found that it is detenting into high range. I went ahead and adjusted it a bit more to try and it still jumped out. I can imagine someone grinding the transmission gears trying to road shift the t handle, but how would this happen to high range? Could it be a bent fork, or would the gear and collar be ruined? |
Replies:
Posted By: 7060
Date Posted: 11 Dec 2017 at 6:10pm
   
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Posted By: 7060
Date Posted: 11 Dec 2017 at 6:20pm
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I decided to go ahead and take the range transmission top off. Picture 1 shows the cogs on the high side gear ground halfway off. Picture 2 is low side gear and it doesn't jump or look bad to me. Picture 3 is shifted into high range detented which leaves a gap between the collar and gear. Picture 4 is shifted into high range beyond detent which I have to hold there as it will pop back to picture 3. Without splitting the tractor and replacing the gear is there any way I can adjust the detent maybe to slide the collar further onto the gear? Is it supposed to be sliding farther than it is, which is the reason this happened? The tractor is really low houred, and I cant imagine someone grinding into high range enough to cause this. I really don't want to split this tractor right now if I can postpone it a while.
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Posted By: tbran
Date Posted: 11 Dec 2017 at 7:05pm
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I think, and that is dangerous sometimes, I would pull the top cover and shift fork, and remove the 70265349 shift rod and move (drill - grind - jb weld up the old hole) the detent a guess of 1/4" so that the fork can shift the collar farther into high. Be super careful not to lose the detent balls/springs and interlock pin. My theory is - barring a bearing down - is the factory set up just barely shifted the lugs into the gear and after some grinding due to faulty tranny brake and abuse, the lugs wore off and in the process wore some on the shift fork. I had a 210 do this and although it is a different set up - on the detent - it worked - so far. 2- 3 hours working on this relocation would be a gamble in lieu of 45+ hours you will be looking at plus parts to properly repair. ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: tbran
Date Posted: 11 Dec 2017 at 7:07pm
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I had to leave and just came back and finished posting when I noticed your pics - I guess great minds..... ------------- When told "it's not the money,it's the principle", remember, it's always the money.. |
Posted By: 7060
Date Posted: 11 Dec 2017 at 9:55pm
| I could be wrong, but its looking like the shift fork has to unbolt from the rail and stay with the tractor? It hooks over the top of the sliding collar and hits the top shaft before it can be raised enough to come out? The fork must have the detent indention in it which will make welding and machining a new groove about impossible. Would it be easier to pull the cab and split it or split it with the cab jacked up and pull the transmission from underneath it? |
Posted By: DrAllis
Date Posted: 12 Dec 2017 at 7:05am
| Remove the small fuel tank and a couple of hydraulic lines. Remove the two bolts retaining the fork to the shift rail. Remove the big round cover and there you have your shifting cover. Make note of the 2 dowel bolts on the cover. Deepen the shift rail notch and weld up and grind where it used to be. Fork can be removed once the cover is pulled off the rear end housing. Still looks like abuse to me. Seen it one time before on a tractor used to haul corn to town. |
Posted By: SteveM C/IL
Date Posted: 12 Dec 2017 at 9:59am
| I would sure try the "detent move"first. Did it to my 45 & 220.Wasn't having trouble but trying to prevent it. |
Posted By: 7060
Date Posted: 13 Dec 2017 at 9:06am
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Posted By: 7060
Date Posted: 13 Dec 2017 at 9:10am
| I moved the detent notch in the rail and deepened it, and I cant get it to jump out now. I don't feel real good about this, but it did work for now. Someone has been grinding the park pawl too a little. |
Posted By: injpumpEd
Date Posted: 13 Dec 2017 at 9:59am
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looks great! There's plenty of teeth there to hold, as long as it goes all the way on them. I bet the inside of the collar is pretty chewed up too. That looks like it had been mis adjusted from day one. ------------- 210 "too hot to farm" puller, part of the "insane pumpkin posse". Owner of Guenther Heritage Diesel, specializing in fuel injection systems on heritage era tractors. stock rebuilds to all out pullers! |
Posted By: SteveM C/IL
Date Posted: 13 Dec 2017 at 11:00pm
| Hard to believe someone would grind that much to remove that much material. Must have thought it wasn't hurting anything? |