I recently rebuilt my 2000 Celica GT engine, I took off one shift linkage at the beginning and put it back on today, now when I try to shift into gear without the car on because I've still got a few more things to put on before it can run, but it feels like it's holding in gear yet the shift knob will not stay in that position, it just wants to slingshot to the middle and you can move the shifter around the whole housing with it in gear, is this just a snapped shift linkage problem?
