661 Ford tractor

I know I posted this a few days ago but now I can't find the post about my 661 Ford jumping out of 3rd gear. There were several replies but
now I can't find them. Can someone tell me exactly what I have to do? Do I have to split the tractor to fix it?
 
The springs and detents are behind the slotted caps on the left side of the transmission. 3rd/reverse is the top cap.


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Unscrew the caps and your will find this assembly.


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The springs pressure the detents into slots machined in the shifter rails. In this case someone had modified one of the slots. I guess it worked for a while, the transmission worked for a few years after I got the tractor until I no longer had 4th gear, hence this teardown/overhaul.

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Inside the transmission. The detents reside in the forward machinings.

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Springs weaken and detents wear. 5 years ago, springs and detents were available new, tho the small gaskets were not. O-rings work in lieu of gaskets. I'm not sure of the situation now. The 3rd/reverse gets the most use, you could swap that detent with 1st/2nd and find out if it improves your situation.

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This post was edited by pomester on 12/19/2022 at 11:13 pm.
 
As a FORD TRACTOR Owner/Operator, the best investment you can make is to get the ESSENTIAL MANUALS and read religiously. Get copies of the Owner's Manual; the I&T FO-22 Manual; and the 53-59 MPC.


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Tim Daley(MI)
 
Great write-up and photos!
For years I have read about the 3/R detent
getting weak on those transmissions but
have never owned one so didn't really know
what was required to repair one.
Is it the shaft that wears or the bullet
the spring pushes on that wears? Or both?
If the parts aren't still available I think
a guy with some basic machining skills
could make either part pretty easily.
If the spring has weakened could you not
compensate by adding a shim?
Thanks.
 
(quoted from post at 06:24:57 12/20/22) Great write-up and photos!
For years I have read about the 3/R detent
getting weak on those transmissions but
have never owned one so didn't really know
what was required to repair one.
Is it the shaft that wears or the bullet
the spring pushes on that wears? Or both?
If the parts aren't still available I think
a guy with some basic machining skills
could make either part pretty easily.
If the spring has weakened could you not
compensate by adding a shim?
Thanks.

I've never had to deal with them myself either, but most pictures that I've seen show the detente plunger (bullet) ends wearing first. I assume that they are made of a softer metal than the rail, but I've also seen a few pictures of the indents on the rails being worn/damaged too, so if replacing the detente plungers doesn't help, the next step would be opening it up and checking the rail(s).
 
What I have seen on the two transmissions I've dealt with is that the plunger wears. It seems to be a rather soft metal. It does not turn/rotate in the bore so it wears across one plane.

Other parts of the shifter mechanism/transmission main shaft wear also, so replacement of the springs/plungers is not necessarily a complete fix.
 

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