977H powershift won't disengage.

Its Killloader!!!!!lol Might have a transmission pilot valve stuck or spring broke.

Check linkage first. Heavy pushing what? Brush? good chance you got something stuck in there.
Going to need a s/n if more involved.

[quote="Old Magnet"]Check linkage first. Heavy pushing what? Brush? good chance you got something stuck in there.
Going to need a s/n if more involved.[/quote]

Concrete rubble, busted up pools. Don't think anything's stuck in there. It's an early model H with hand steering clutches, hi/low range transmission and two speed powershift. Guess I'll pull the floor plates, take a look. And get back to ya.

Hi Team,
it is quite common for high hour power-shift machines suffer these problems when the linkages wear. Also when the bearings for the shafts, and indeed the shafts themselves, taking the shift motion into the transmission itself wear.
I have found at times the operator needs to flick the shift lever to get the valve spools to move full travel past the detents in the valve group inside the trans. to get to the desired selection.

Loose platforms also add to the mix as they move with a change of machine working angle.
These machines were prone to breaking the rear seat frame/fuel tank framework mount points allowing the whole unit to move and alter the linkage adjusted positions. The rear frame mount bolts can also come loose and cause this.
In extreme cases the movement can shift the operator's selected trans direction and/or speed.

As an aside at The Dealer we saw a couple of 769 dump trucks down shift the range trans. and over-speed the engines with catastrophic results, this due to loose platforms.
Cheers,
Eddie B.

Linkage is tight, and the spools on the control valve move the full travel, so that ain't her trouble. The service manual says something about a safety valve that automatically engages neutral when pump pressure drops below 50lbs to prevent starting in gear. Looks like it's located directly behind the speed control valve spool. Looks like a spring poppet relief valve judging from the parts book. I know my problem is getting it into neutral, but I'm thinking that maybe this is the culprit, either weak or stuck depending on how it operates.

The trans filler tube is right there behind the access plate, but it looks like there's clearance. Does anyone know if this is serviceable in the machine? Would I be asking for trouble to replace that spring in place?

Thanks.
Chip

Can't tell you about access but I think you are on to the culprit.
Does state that if the spring in the safety valve becomes weakened the valve may not shift the speed selector valve to neutral.

Hi Team,
from your description it would appear that the symptom got worse the more you used the machine, something you could maybe check whilst in the top of the trans, is the adjustment of the speed and direction spools for correct central adjustment--a spool adjusting thread may be loose and the spool has unscrewed some.
I do not have a books for this late of machines to scan the procedure from. But in neutral, certain ends of the spools should be aligned to machined surfaces the valve body end faces.
You should be able to see the relationship from your Parts Book pix if it has a sectioned view of the valves or from a plan view.
Hope this helps,
Cheers,
Eddie B.

You stated you have the service manual so it would be worth checking the specified dimensions for the linkage.

Can I get a little parts book love?

My ser# is 53A 2236. My service manual for 53A1 and up shows two different types of control valves, one with a flattish cover behind the speed spool/safety valve assembly with one spring (Group 105.1) and another with two springs and a longer nosed cover (Group 105). My parts book is for a 53A 3000 to 4976, and only shows the longer nose version, effective with test version 7747 ( whatever that means)

Of course, guess which one I have...Would appreciate it if someone has the correct part number for the spring and seal for the valve assembly with the flatter cover and single spring.

Thanks.

Chip