i noticed that mt tranny always grinds when i put it in reverse,why?,even when im at a dead stop and with the cluch all the way in

 

Put it in a forward gear first.

 

as RB83L69 put it. Put it into a forward gear first, reverse has no syncronizer on a T-5. Just go from 5th - R.

 

so put it in a gear than reverse instead of netural than reverse

 

Yup, just put it in any forward gear (since they're all synchronized)to stop all the trans guts from spinning, then take it out and immediately put it in reverse. If you have the clutch out with the engine running and just push the clutch in, all that stuff is still spinning, and takes several seconds to coast down to a stop; meanwhile, if you try to just jam it into reverse which has no synchronizer, it's going to grind the teeth down while everything is coming to a stop. That screams to everybody within about 500 yards "I don't know how to drive this car!!" in addition to filling the transmission grease with metal chips and destroying the reverse gear. I'll have to go take a pic of what it does to one, I have lots of them laying around, and some of them have that damage on them.

We all go through the learning process (we hope....).