127 hydro issue

[Cubstudent]

Hello, I'm not sure what I might be experiencing with my newly acquired 127 which hasn't run in years. Repaired K301 which was missing ignition parts and carb had issues so I finally got it running very well. Took a ride around the yard forward and backwards at a slow pace,seemed fine. I got something going on in the hydro as when I raised engine speed while in neutral ,I found that the when I wanted to go forward or reverse,it was like in neutral. After I slowed the engine speed and did it again,it moved normally . I was able to raise engine speed and forward and went faster,so I thought it was just a glitch from not running for so long. But I duplicated it several times, also get an intermittent grinding noise as well as clicking felt in the speed control handle when it seems like gear teeth are not engaging properly, but I have a hydrostatic trans and when driving around slow,no noise from rear end and everything is smooth and operates proper forward and reverse. Fluid is clear and high enough to run out rear diff plug
Any ideas on what I might be experiencing ? Thanks

 

[lhinds]

Sounds like a coil .pin sheared in rear end of driveshaft

 

[Cubstudent]

I'll check into that. That sounds like what could give that feeling when it slips ? I'll let you know when I get more time to get into it again. Any tips on looking at it or should I get it apart to actually find it broken? Thanks for your help and most likely issue