Transmission Noise on Cold Start

Hey yall, I know I've been posting a lot but I'm still learning a lot about this truck. Recently, my truck has started to make a transmission grind type noise whenever I put it in reverse on cold starts. It'll slowly make the noise when I have my foot on the brake but it'll stop whenever I roll back. It's a slight noise but annoying. It'll also make the noise slightly when I shift to drive after reversing for 1 second and then I won't hear it for the rest of the day. I've been reading threads looking to no avail. I recently did a transmission fluid and filter change thinking it would help but it didn't. It shifts fine, still accelerates the same, just annoying. Anyone else have this problem? Is it just gonna be one of those annoying Tacoma noises I'll have to deal with forever? Thanks in advance

 

Cat cover?

 

Yeah I do have a cat cover. Would it cause it to make that noise? I had to take it off and it didn't really do that or at least I couldn't hear and then I put it back on

 

When you get a chance slide underneath your truck and take your fingers and start tapping really hard on that cat shield and see if it rattles around even the smallest rivet missing to hold it on would make a rattle something easy to check keep it simple first

 

Are you sure you did the fluid level check procedure correctly after doing the flush and fill on the ATF?

Normally I would agree your noise is not related to the trans and is probably just a small rock trapped somewhere

 

I didn't do the Trans fluid change myself. I took it to my trust mechanic and he did the work. Normally I would take it a dealer for a job like that but he's a Toyota certified tech and I really trust his work. And yeah I don't think it's Trans as I said it shifts perfectly. I saw some scraping on my cat where the cat shield connects so I'll take the shield off and see what happens.

 

*Update. Found out what it was. The catalytic converter shield was rubbing on the cat and ended up bouncing up and down all the time making this noise. I took off the shield and the noise went away. Thanks for all the help!