I was giving the mustang a trans. oil & filter change and found a plastic piston with
a oring on it on the bottom of the oil pan anyone know where it goes????

 

I've seen this on both Ford transmissions I've worked on. I was told that it is from production and that it's easier just to pop the plug into the bottom of the pan vs. removing the pan, seal, etc. to remove it. It is supposedly used to plug the filler tube hole until the filler tube is installed from the engine bay, popping the plug into the bottom of the pan. It's to large to cause a problem with the pickup or filter. I know it's a bit nerve racking to find that bouncing around the bottom of a transmission filled with pistons, seals, o-rings, and the like.

Good luck

 

yeah found one in my 5.0 long ago. scared the crap out of me til i found out what it was!

 

Thanks Guys its been really bothering me to find that in there... But that sounds right.
Thanks again

 

Another tid bit, use your new found knowledge the next time you need trans work done. I often research as much as I can before I take my car to the shop just to keep the mechanic honest. Right after I found that piece on my 83 T-bird I had a few transmission problems. Took it down to Ford, they had the best trans mechanic in town. The first guy actually said that part was the shift piston for the 1-2 shift. I figured he was full of shi* but wasn't 100% sure, it still shifted from 1-2 but at nearly 5000 RPM. I finally made my way to the REAL mechanic and he knew extacly what that part was and exactly what the problem was after just driving the car 2 blocks. He jumped out and looked under the hood. Turns out that I had knocked the kickdown linkage off the carb. He didn't charge me and I learned that a real mechanic won't BS you. Now I ask a new mechanic about the little part found in the transmission pan and if I get some line of BS, I walk off. There's an awful lot of beef out there if you get my meaning.

 

Yep.. exactly why it is there.. you just push the trans fill tube in place and pop that into the pan.. Won't cause any problems. I was a mechanic for Ford for several years and rebuilr more than my share of trannies. Don't sweat it