MF 135 loader 3PTH not working

[kaymcc]

I recently bought a 1970 perkins gas MF135 with a loader. The loader and tilt worked fine while I was buying it but I didn't test the 3pth before buying. After I got it home, I decided to try the 3PTH. Moved the option valve under the seat to the 3PTH position and it worked. Moved the valve back to loader and loader and tilt wouldn't work. Went back the next day and loader worked and 3PTH worked a couple of times and then quit. I removed the option valve and stand pipe and all looked OK. Re-installed option valve and all worked OK again a couple of times. Then quit again. Haven't changed out the trans/diff fluid yet but looks pretty grey too me. I highly doubt it's been changed in many years. Hate to dump it and put new fluid back in and turn around and dump it again if some internal work is needed. Could bad fluid or an air lock somewhere cause this trouble? Any ideas on what's going on?

 

[Ray,IN]

Get a service manual, it shows how to check the standpipe below that selector valve. That standpipe delivers pressurized oil from the pump. The top of the transmission doesn't have to be removed to check that.

 

[kaymcc]

All OK now. Standpipe was OK. Beginner error. Never had a loader before and there was no instruction manual. Didn't have hydraulic control levers all the way back. Thanks for replying.