Nissan Repair: 1994 Nissan pickup manual transmission

Question
Won't shift when driving fluid is good pedal is good master cilnider is good

Answer
Hi Shawn

Assuming the clutch is OK as you indicated and is engaging, the problem is probably in the transmission sync. This means the trans will need to be taken out to be repaired.

If you can shift it in gear when the engine is off, then start it normally, then that is an indication that the synchromesh is out.

Hope this helps -
aloha
Calvin