FWD Trans Just Lost 5th Gear

[mnetwork]

I was able to source some used parts to fix the trans. The trans is now all back together. I filled it with fluid, but had my doubts about the cleanliness of it, so I ran the car with the wheel off the ground, went through the gears a few times and shut it off. I then then popped the drain plug to see how the fluid looked and it still had some sliver flake in it.

What would be the best way to flush the trans? I'm pretty sure I shouldn't drive it while the fluid has some silver flake in it...

 

[mnetwork]

Alright, I wound up buying a gallon of some cheap Pep Boys brand 80-90 gear oil and did two flushes with it and a little leftover MT-90. Last flush didn't really yield any flake. Took the car for a drive, 5th and reverse are shifting nice and smooth along with all other gears. The car is finally back up.

Thanks everyone for your help.