I have an M5R2 in my truck and after fiddling with the clutch, it will no longer shift. What's going on here? It's completely jammed.

 

What do you mean "It's completely jammed" ?

With the engine NOT running, can you move the shifter through the gears?

If you can shift with the engine off, but cannot shift with the engine running, then your clutch is not disengaging.

You said the problem started "after fiddling with the clutch". What did you do to the clutch?

 

Need more details, but on a guess. I have had two import transmissions that the shift rails did not fully disengage and jammed the shifter. If this transmission is a top loader ( I have not Idea about a M5R2) then you can pull the shifter out of the top and line the shift rails up properly. They usually look like they dont belong when they are jammed. Just move the rails so there is a big opening for the shifter to sit it.
Just a guess.
My $ .02, value .... $ .0000000000002 Please do not redeem for cash!

 

I'm sorry, I should've been more clear. This is with the engine off. Since the truck was originally a mechanical clutch and I wanted to simplify the parts on it, I made it up to 87-91 specs. While trying to bleed the clutch, it blew out the clutch line and that's when it stopped shifting anymore. I'm trying to get this mess lined out so I can actually get the motor up and running.

 

Everything worked until the hydraulic line blew out. I am having trouble thinking of any way that the clutch hydraulic line blowing out could cause the trans to jam.

I have never worked on an M5R2. All I can think of is that, just by pure coincidence, a shifter fork or other part of the shift linkage slipped out of place and has jammed the mechanism. You probably have to pull the top cover off of the trans and get everything back into its correct position.

Once a long time ago, I had a trans with the shifter in the cover and there was some slop in the forks and gates. I pulled it out of 1st gear and did not get quite all the way into neutral before I moved the shifter sideways. The shift lever went into neutral, but the shift fork slid back into 1st gear. I was stuck with the trans in 1st and the shift lever in neutral. I had to pull the top cover and move the shift fork back to neutral.

 

Maybe it just needs to be running so the gears can line up, I'd fix the slave cyl leak and see what happens