hey sir duodeluxe...maybe the inching cable stuck sir...try to replace or clean or apply with oil for smooth operation...the problem i think is not in the transmission...if you have a burn clutch pack you can notice it in the ATF. maybe the probelm is in the inching cable and in the brake. the lining will not immediately back when you use a brake or the inching pedal..try to adjust the brake lining first sir..Got a problem with toyota 7 series forklift i just clean the inching cable and applied an oil.

best regards