Weird thump thump!!!! NEED HELP QUICK!!!!!

[Devilpup08]

Hey guys wondering if you can help me. I know very very little on my truck or repairs but I'm going to fix that soon.

Anyways so I'm sensing a problem with my 96 ranger.
It's a 4banger with a manual transmission and it has roughly 123000 miles.
After I brake at a stoplight and I'm sitting in 1st gear when a random thumping starts to happen. To compare the sound it's kinda like throwing a tennis ball around inside a cardboard box. I think I can feel it in the pedals but not too sure. The location of the sound from where I'm sitting in the drivers seat seems to be almost behind the radio or under the stickshift column. I'm gonna take a wild as guess and say that it's the clutch or tranny. Please help.

 

[Moreflying]

If the clutch in engaged and in gear is the truck moving at all? Is it hard to get in 1st gear? If so you might need to bleed the slave cylinder or need to replace it. If that is the case you may as well put a new clutch pack in. That would include a new throw out bearing, clutch disk/pressure plate and pilot bearing.

 

[tomw]

If the noise occurs after sitting for a while, rather than immediately, then I would suspect the slave cylinder was leaking down. If it happens immediately, with the clutch pedal depressed, I would be thinking about the pressure plate being loose on the flywheel.
Does it make the noise if the transmission is placed in neutral, and the clutch pedal released? Have you crawled under and looked for things flopping that shouldn't?
tom

 

[Devilpup08]

The noise wasn't immediate, it would happen a few seconds after the truck comes to a stop at a light. In neutral with the clutch pedal released a whirring noise happens. I've driven the truck for 2 days without the thumping happening at a light or when I tried to repeat the noise. When I get the money I was going to replace the clutch entirely.

 

[Devilpup08]

It happens about 30 mins after driving.