iDRY Vacuum Kilns

Sponsors:

John Deere 440A tranny troubleshooting

Started by lovetotinker, June 01, 2018, 08:59:02 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

lovetotinker

I have a 1968 John Deere 440A cable skidder with a syncro-range tranny. Supposed to shift smoothly between high and low range. Synchronized. However it will not stay in high range. Pops out as soon as you let the clutch out. I took the top off the tranny and looked the insides over. Every thing looks about as it should. The shifting linkage seems to stay in the appropriate detentes and seems adjusted according to the manual. Would the syncro disks be the cause if they are worn?  Or would someone with more experience out there have another suggestion or advice? It does stay in low range just fine. Would be nice to have both.

mike_belben

I had a smoked synchro medium duty truck trans that would do that and worse.  If the dogs on the side of the gear and/or inside of the sliding clutch collar are mushroomed over they wont play nice and jumping out of gear is on the list of behavioral problems.   

Look and be sure that the shift fork fingers, links, yokes, pins etc all are in good shape and dont have a wear stackup that is preventing the fork from pushing the sliding clutch all the way to its home.  Also be sure there isnt a missing plastic or brass piece that takes up clearance between the fork and the groove in the sliding clutch OD. 
Praise The Lord

Satamax

I don't know zilch about JD tranies. 

But on Toyota ones, a  very usual problem, is the spring behind the locking ball, which is on the fork's shaft; wears off or breaks. 

That would the first thing i would check, if the architecture is the same. 
French CD4 sawmill. Latil TL 73. Self moving hydraulic crane. Iveco daily 4x4 lwb dead as of 06/2020. Replaced by a Brimont TL80 CSA.

mike_belben

Yeah that is a good point too.  Detented rails may be employed in the top cover.  
Praise The Lord

lovetotinker

Thanks for the input. The detente springs and balls I did check, although the manual suggests giving the springs an actual tension test, they seemed stiff enough. I don't think they could be the problem because one shifting system works fine and the other works fine in low range. If the spring for that system where bad it wouldn't hold it in low range either. I think the problem must have to do with that syncro or as Mike_belben suggested, the shifting collar and other related parts. I will take the top off again and compare the parts diagram to what I see. 

East ky logging

I have a 440 b that don't want to stay in high range it will stay in as long as you're giving it the fuel but when you let off it will usually kick out. I never have gotten around to checking it out but I would like to get it fixed. If you figure out the problem could you post it on here so maybe I'll know where to start looking and maybe help someone else someday.
They who can give up essential liberty to obtain a little temporary safety deserve neither liberty or safety- Benjamin Franklin

Firewoodjoe

I had one years ago. Would kick out and sound like a squealing bearing. It was the fork. Worn just enough. Had it welded and machined it worked great.

lovetotinker

Thanks, I'll check out the forks when I next have it apart. Probably won't be till July, and will post what the problem was when I figure what it is....

Thank You Sponsors!