BX23 '1st clutch' slips out...?

[tshep]

Yeah, I know there's no operator clutch, but listen.
Around 600 hours.
I'm mowing, say 2 hours steady, wet grass, motor not 'hot'.
On 'quick' turns, I lose steering, mid pto, and drive - comes right back.
Tried high and low 'gear' - still happens, less if I just slip around corners (?).
Gotta' be level, right?
Stop for a bit, look 4 times, wiping stick carefully, right up to the lower mark, on both sides of stick, so not just hole drippings. No foam, no clues.
Move the truck while I'm stopped, after just a few minutes, starts slipping out again.
I checked, and it drives the mid pto in 'neutral', so I don't think it's the low high selector, lift was centered, not whining.

Got any good clues?

 

[ptsg]

Checking the service manual, looks like that tractor uses a single hydraulic gear pump with a flow priority valve for the HST charge pressure, steering and PTO clutch pack. The rest of the flow is used for the 3pt, loader and remotes.

An issue with the priority valve could cause the "slipping" effect of the transmission along with losing steering and PTO.

Have you done the basics and checked the hydraulic fluid level?

 

[tshep]

...
Have you done the basics and checked the hydraulic fluid level?

Yes, that was the 'stick, lower mark, both sides' part.

(I will try to think through your reply - done.)
Any reason a priority valve would respond to quick turns?
I do/did not have loader, remotes, or 3 point on - but I could try mower lift (3 pt cyl) during next event. But, based on your research, sounds like ALL hydraulics could be going - both outputs of valve, thus probably the input.

 

[Eagle1]

Did you check the hydro cooling fan just in front of the rear axle? When a stick (or something) rips off the fins the hydro pump gets too hot to work well. On warm days at least.

 

[Robin Veerman]

…and add a qt or two of oil until it’s at the full mark. Not sure why you’re happy to leave it at the lower level