Help!!! Clutch?? Slave Cylinder??
 

My 93 cummins will not go into gear while the truck is running it's a five speed, I think it's the clutch but it could be the slave cylinder has failed also, however there is fluid in the reservoir and it is not leaking.. I heard the slave cylinder can fail when fluids bypass the pistons and you can't see any leakage... Just wondering if anyone has had this problem before thanks

Slave cylinder for sure

How can you be sure?? There's a possibility it could be the clutch right??

BC it won't go into gear at all usually if clutch is going you can get it in sometimes and besides y wouldn't you replace a $50 slave before pulling the trans and putting in a $400 clutch kit. I'd do the 50$ n less labor first even if thts not the problem somehow if clutch is junk then the slave will fail shortly after from my personal experience