M35A3 Thottle sticking / Not returning

[Notorious]

Hello all, new M35A3 owner here and I have an issue. When the accelerator pedal is depressed it does not return. I've run though the the entire throttle assembly but cant find anything obvious, return spring seem to work by hand. There is a secondary cable on the underside that seems to run to some kind of assembly attached to the transmission pan, not sure what this is suppose to do? Any suggestions on where to start would be appreciated. Thanks

 

[Maverick1701]

maybe rust inside the cable sheath?
We had a 900 series 5-ton that had sticking issues (when using the hand throttle). We sprayed the lube inside the cable sheath and after a few times of pulling/pushing, it cleared up.