10 Speed popping out of 4th & 9th...Need to Fix

Having same problem but mine pops out on the 5th and 10th gear very useful info

 

My Eaton Fuller 10 Speed would come out of gear under light load in 3 & 8. It didn't 'pop' out with any force. More like 'walked' out of gear and back into neutral.

Thought I'd throw a Hale Mary pass and replace the detente springs and plunger, before replacing the entire transmission. There are no balls in the detente design.

Fairly easy process, as my International 8600/Transtar affords enough room to access everything through the floor.

Four bolts to remove the top cover. One bolt to remove the shift block, which also contains the two springs and plunger. The plunger from my truck's transmission had obvious wear. Replacement was straight forward. The smaller diameter spring sits inside the larger diameter spring, and together they press the plunger against the detentes of the interlock key on the shift shaft.

My problem turned out to be the worn plunger and springs. The shifter no longer walks out of gear. Saved myself $3500 for a rebuilt transmission, plus a new clutch and the labor to install everything.