Popping out of 3rd gear

I had a loose U-Joint compression bolt when mine was doing it.


Rocky

Check your trunion bushing for wobble. If so tighten. I've seen failures where the rubber bushing left the housing as well.

wouldn't any looseness in the linkage have a "tell tale" of the shifter being able to be pushed to touch the gate?

I can't help but think transmission gears just don't 'pop' out of gear, IF they have been fully engaged.

IF fully engaged, I fail to see how the minor shift linkage vibrations caused by a worn trunion, and most questionably, by a loose u-joint, can impart enough force to dis-engage a FULLY engaged gear set.

Will someone please school me as to what I am missing?

Larry

my "thinking" is lost motion in the loose linkage does NOT allow full engagement of the "sliding sleeve" onto the "clutch body"

All the possible reasons listed to date are correct. But the most likely is misadjusted shift linkage, or a loose or badly adjusted trunnion support. As mentioned, ANYTHING that prevents a full-length move of the shift shaft into or out of the rear mounted shift box will not-quite-fully engage the synchro slider for that gear inside the tranny. Then under high torque, the syncho slider will move backward into neutral.

I've also seen minor wear and/or linkage misadjustment that prevented full gear engagement unless the AFTERMARKET shift gate being used was trimmed to fit a particular Pantera.

Update:
The shift rod u-joint was running into the wheel well. Minor adjustment appears to have solved the problem.