1995 Mazda Truck Timing chain?

So far we have eliminated clutch problem, timing chain has just a little slack but not broken. Motor is completely locked up, will not turn any way at all. Truck is in neutral, still locked up. We are in process of removing motor to see what is up. Have never had trouble with it, plenty of oil, no previous noises until death roll. Of course since we have it apart will replace clutch etc and timing chain.

Any other ideas? We just can't figure out why it would lock up while running, normal highway conditions, level ground. Must be just our luck. ;-)

Spark plugs out, oil out and fine, radiator out, clear water. Yep, guess we're going in deep. I thought sure it was the timing chain from the sudden noise, like something breaking but no, it's ok. So looks like something inside motor. Guess we can just hope something we can fix or replace without replacing whole motor.

Thanks, let you know what we found tomorrow, shop is closed for the day!