Hey everyone, I am in the middle of overhauling my C4 transmission from an 81 F100. This is my first and I'm having a lot of fun and learning a lot, but I knew eventually I would probably run into something that threw me for a loop.

So after removing everything and cleaning it all up I noticed this very pronounced wear on the inside of the transmission case. It is exactly the shape and size of low-reverse band in the back of the transmission. So here is my question. How possibly could this low reverse band cause this wear?

As you may see in the pictures below, the groves follow the gaps in band. Is it possible the band became attached through heat/rust and then came loose and just spun around inside the case? I wasn't looking for this problem when taking the trany apart, but I do remember the low-reverse band being in the correct alignment. Very weird. Any ideas as to the cause and just as important...is this a big deal?

 

That was machined at the factory.

 

What would have been the benefit of doing so?

 

For added band clearance.