[Jason]

The t-45 manual transmission in my '97 mustang gt grinds gears a lot. I've owned more manual trans vehicles than automatics and I seem to grind this one a lot.
A few weeks ago I lost the reverse lights and traced it to a blown fuse caused by a shorted reverse light switch, it's mounted in the side of the trans.
Today it would not go in reverse, I had to pull down on the stick and hold it. It did this once today. usually it's hard to get into reverse but this one time it would not stay in at all.
Could it have something to do with the rev light switch? binding up or something. It seemed to want to grind fifth today too.
It's got 87,000 easy miles on it, I've put 5,000 on the car.
The fluid has probably never been changed but would it cause it to do this?
The shifter has no slop in it either.
I checked the adjustment of the clutch cable and it seems ok.
Any ideas?

[woodz428]

It could be something internal or possibly the switch (though I wouldn't think so). Something often overlooked in these cases is a rear main leak, even though minor ,over a period of time it can get on the clutch plate and make it "drag" when shifting causing gear grinding. Usually, but not always, it will be worse when cold and as things heat up lessens.