Clutch, tranny, pressure plate, starter?? Im not sure please help!

Please help! Last night i was taking a cruise with my brother and his friend. I didnt take any hard dips or pot holes or anything and i would take them slowly or avoid them when there was one. As i was driving i heard lots of rattling, not shaking but rattling under my car. We all noticed the sound after we all had to beat a yellow light. I kept driving and was going to pull over to stop to check out the noise after the next light. But as soon as I was going to go after the light my car stalled. I tried to start it again but the car would rock slightly forward then back when it wouldnt start. I kept trying it again until i popped the hood. I thought maybe it was my timing belt because its going bad and i was going to replace it soon. Once i pooped the hood something smelt slightly burnt but there were no fluids dripping at all. We tried to jump start it but my car made a loud crank. After looking into it we noticed that the crank was coming from my starter and i have a large crack in it so we thought that could be the issue. The weirder thing is that i noticed my clutch isnt as stiff as it used to be as well. We called triple A and the guy said it wasnt my starter but we said there was a large crack in it. He didnt have any knowledge to help so it sucked. But as he tried to tow my car it wouldnt move and he kept checking but my car was in neutral. We realized that I had to be in the car pressing down the clutch and it had to be in 4th gear in order for us to tow the car onto the flat bed. Could it be my pressure plate? Something within my tranny or just my clutch being out? Any inputs would help.

Youre going to have to pull the trans either way to figure this out

Best to just do that and tell us what you find as something is definatly wrong there, we will just be taking shots in the dark at this point.

Pull the starter off and bench-test it. Easy enough.

But if the car rolled better when in a certain gear, or with the clutch pedal depressed, the issue is almost guaranteed not to be the starter.

hmm. the fact that it only moves in 4th gear is interesting. 4th gear is a direct drive gear. mainshaft is locked to input shaft when this gear is selected, making it 1:1. that is, mainshaft turns at engine speed. hmmm. the rattling noise prior.
i wonder if the pocket bearing is seized. this bearing separates the input and mainshaft. so they can rotate independently of eachother in all other gears except 4th, when input and main are locked together.

yea, thought about it, and that’s my stab.
the car rocked when attempting to start because the input and main shaft are seized together. the high mechanical resistance to the starter cracked it.
that’s my guess anyways…
please do update though when you find the cause! i’m very interested to know!

any update on this? i was interested to know the culprit