A340F trans . Do you know what this is?

You guys know why this is? I just had my valve body rebuilt. Truck drove fine for a week. While in 4 Lo, parked truck. When I came back, found I had no reverse, it drives forward in neutral and does not go into overdrive! Dropped the pan and found this.

 

It looks like the letter "L".
I can't identify what it is, but I wouldn't try driving it again until its figured out.

 

Sounds like your shifter linkage is not correct. If you go forward while in N, then you are acutally in D. When you're in D, you're acutally in 2. When you're in R, you're actually in N.
Make sense? You need to go under the truck and find where the linkage bolts to the lever on the side of the transmission. This is on the driver side. Loosen the bolt and adjust accordingly.