Hey there, so I started up my 2005 Colorado on a really cold day and let it warm up, but it wouldn't go into any gear. Changed trans fluid and it was totally black with a metallic look(very fine particles). Also a couple small (1/4") metal shavings at the bottom.

It ran after that, but if it idles on park for about 5 minutes, it won't have much power.(like if you had it in drive but didn't step on the accelerator, it goes forward very slowly, even when revved) Turning it off and letting it sit for a couple minutes will fix the problem.

Also at about 55 if I'm going uphill or accelerating there is a shutter. Like hitting rumble strips, but not as violent. I put shutter fix in, but it didn't do much.

Appreciate any help. Thanks!