No First Gear

1997 F350 7.3 / E4OD
About 5 weeks ago I was out doing burn outs to set my wast gates. Hold the brake blip the throttle the tires brake loose and start to spin no problem.
2 burn out and no problem. The 3rd I noticed it took a hole lot more throttle to brake the tires loose. Did not think much of it and drove it for another week. Then went to load the truck onto the trailer for a truck pull. Use to 4 low and the truck just idles up the ramp and on the trailer. This time I had to give it a lot of gas to clime up the ramp. it was like I was in high range.
Driving it around town and it seem like it starts in 2nd and not first. Pull the gearshift into 2nd and it starts the same way. The trans does not slip, and it drives with no problem, It just does not use 1st gear.
So no first. I think it is there, its just not in use. But why. Checked the dip stick and it is clean. Drained some fluid out of the pan and it is clean. The OD light is not flashing and there is no check engine light on.
So what happen? Is it mechanical or electrical?
Please help.

the technical term for it is

"broken"

and yes, it's probably mechanical....

Did you ever figure it out?

mine did dat once and i still havent figuerd it out compltely but for sum reason my trailer brake is wired into my tranny and i unplugged it one day and went to drive it would start out in 2nd pluged it in works fine dats how i bought the truck 97-f250 7.3 e4od 4x4

Pulled the pan. No chunks just some black crap on the bottom. Put the pan back on and drove it around again. Still the same. I know it starts off in second and from there up it shifts fine. Reverse also seems to work fine. But now when I pull the shifter into first gear it seems like there are 2 clutch packs engaging at the same time. Add a little throttle it feels like it locks up and will not move, then give it more throttle and the line pressure goes over 180psi it trys to move. It feels like I had a clutch pack come apart. Don't know it that is passable but that is what it feels like.

As of now it still drives so that is what I am going to do for now. Will see.

Update
Was driving it around town. Ran down a ricer for fun. came to a stop light and when the light turned green the trans slamed into gear. I thought that I really broke it this time. Believe it or not my first gear is now working again.
I guess that it was just a stuck valve.

Will run out the year on this trans then it will have a new trans for next year pulling season.