Technically challenged SOS repair

jeff pk

Member
Attempting to replace the servo #3 valve pin behind the
interlock cover. Drained the oil---very black with a little non-
metallic debris on screen. Next step is cover removal. Dean
has warned me not to pry it off as it's cast and could easily
break (Thanks!), but the thing looks very complex---like there's
a lot behind it, and I'm worried something will pop out or fall off
and I won't know how to get it back on. Are there any concerns
besides breakage?
 
It will likey be stuck very tightly.

Make certain that all bolts are removed.

Tap, don't drive, a tapered chisel in several places around the perimeter of the cover between the transmissioni case and the cover. Place the chisel on long, straight sections of the cover rather than "ears."

Keep moving and tapping. Patience is a virtue.

Dean
 
It's pretty snug. Tapping with a wide chisel got it to just barely separate along one edge, enough for a little oil to seep out of the bottom. Had to go do something else so I'll continue with it tomorrow. Thanks for the advice.
 
The strong springs of servos 2 and 3 push against the interlock cover - the springs apply bands 2 and 3 for Park, for example.

The interlock bolts are of two different lengths - suggest threading in the long bolts a few turns while working to loosen the interlock cover to prevent it landing on the floor when it pops loose from spring pressure. Don"t use the short bolts.

With the cover off, don"t pull the servos out of their bores because each have a band strut that can fall out of engagement. SOL at that point. Check the manual for a look at the struts.

When installing the interlock, you"ll be pushing it against the springs which (I think) will make it difficult to get the bolts started. If so, use longer bolts to pull it in until the original bolts will engage, or back off the B2 and B3 adjustment screws to relieve pressure on the springs. Same as above, to prevent the struts falling out, push the servos inward when loosening the adjustment screws.

That little pin you're after was supposed to have each end boggered a little ("staked") at the factory to prevent it working loose.

Besides a chisel, maybe try a narrow putty knife, like 1-1/2 inches wide, with the end or one side ground to a knife edge. Putty knives are strong springy steel and should tolerate the pounding. Consider it a sacrificial tool.
 
Your manual should have instruction for releasing the spring pressure on those servos,without dropping the strut inside the case. If the cover pops loose with full spring tension,you may experience some painful injuries.
 
Great explanation mooger. Really nice to know what's going on behind that cover. I'm thinking I have the wrong size pin and might try a 3/8 drill bit cut to size---Is that completely insane?Will keep you posted on progress...
 
jeff pk wrote:

"I'm thinking I have the wrong size pin and might try a 3/8 drill bit cut to size---Is that completely insane?"

Not insane, I suppose, but good luck if you mean a 3/8-inch diameter bit...the pin is about 3/32-inch diameter by 1/2-inch long.

The pin didn't float away if it's actually loose, so odds are it'll fall out when the interlock is taken off.
a111714.jpg
 
So I got the cover off, but think I maybe blew it. Was releasing the Band 2 adjusting screw per manual instructions and think I may have brought it out too far---I heard something drop behind there and when looking at fig FO212 I see #17 strut there. Did that fall down, and is there any way to get it back short of a split and teardown?
There was NO spring pressure at all behind the cover. Both servos are firmly in their slots---they did not pop out at all. The valve pin also seems intact---interlock valve (#1 FO211) moves along the pin axis only.
 

I've forgotten - why did we suggest this pin to begin with? Are you missing 5,6,7 & 8? If so remind us which tractor you have again. If this is the scenario, B2 is failing to apply for some reason. The little pin is the most common culprit. Since this is a spring applied band, one would guess a sticking B2 valve keeping hydraulic pressure applied as the next most likely cause. Either that or the band is shot, broken or not adjusted properly.

Since you believe you've dropped a strut anyway, you'll likely get the chance to look the innards over well. Check it all out. Let us know what you find.
 
Yes, it was going to neutral in 5,6,7,and 8. The Model is 881
gold demo. Does it sound to you like I dropped a strut? Is
there a way to be sure I dropped a strut short of putting it
back together and trying it out?

I'm not sure I'm up for anything major on this transmission---
not with this cryptic manual that has no "Caution" warning
when it says to loosen the band adjustment screw.

Here's what the manual says: "Remove the lock nut and
sealing washer from band 2 adjusting screw; then back screw
out until it is free"

I backed it out until it was free and the strut drops off???

That's just terrible instructions.
 

I don't own any IT manuals so can't help on that one.

If you heard something drop, I'm guessing it was the strut. If you turn the B2 adjusting screw back in and it goes considerably farther than it was, you'll have a definite answer.

Not sure where you're located. If you're close I'd be glad to take a look see.
 
Thanks for offering to look it over.

I tried screwing it back in thinking the servo might extend out,
but it just stops screwing. It's hard to tell if it's going in much
further than original as the cover is off.

I'm in Oregon.
 

OK, here's another suggestion. Jack up a rear wheel. with the band adjustments tight, try to turn it. Will it turn. If so there is a problem with B2 or B3. (Traction Disconnect must be engaged)
 
Okay I'll try that. Do I need to put the interlock cover back on
or can I do it removed with the adjusting screw just turned in?

Leave it in Park?




Thanks
 

interlock cover does not matter for this test.

transmission is always in Park when the engine is not running, no matter what position the shifter is in.
 
if you're sure both bands are tight, you shouldn't be able to turn that wheel.

I'm gonna guess you dropped the strut as you suspected.

Wanta haul it to Kansas??? :lol:
 

Transmission split from center housing at rear. Rear gut until you get in far enough to fix your problem.

You'll need a rear transmission housing gasket, a transmission to center housing gasket and oil for the hydraulic section as a bare minimum.
 

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