I got a 05, 6MT and i jus recently did a clutch swap about 7-8 months ago to JWT clutch, light flywheel the whole 9. Within the last month or so, I've just noticed my 5th gear making a grinding noise once i put it in 5th ONLY ONCE and ONLY the first time i put it there. After it makes that noise that one time, it will will be fine and not make it again usually that entire day. I can shift to 5th 1,000 times and it will never do it again. Not untill the next day after everything seems to have cooled off and is cold again...its does it once, and then its fine again. I can feel it grind in the shifter as well. I dont wanna be messing anything up. Does anyone know wut this may be?

when was the last time you changed your trans and diff fluid?

Not since i've had the car and thats going on 2 years this January. U think that may be it?

2yrs = how many miles?

Well who knows if the previous owner changed it either ha. Fluid is cheap transmissions are not.

75k miles

lol...yah time for a change...should be done about every 30K.

change oils or bad news your 5th gear syncros is going out

I'm having the exact same issue. Grind's into 5th once after I start the car, and then that's it for the whole day. I'm at 85k miles, and don't believe my transmission fluid has ever been changed.

Changing these fluids fixed my problem. No more grind into 5th