Chassis help needed, I think

[freelosophy]

So my mt410 drive train is making louder than usual sounds and it seems to rattle too. I thought it was the front drive shaft so I swapped it out and I think it may have helped a little (maybe) but still something not right. I check the chassis with a straight edge and it is just a little dip in about the middle. So if any of you guys have experienced this I sure like to hear it. Am thinking that just a little dip in the chassis should make that much difference but maybe it it. Had anyone experienced the symptom of loud drive train noise caused by the chassis being bent? I can replace, but hate to go through all that and it be something different. Any thoughts, pointers or whatever is appreciated. I've troubleshot and replaced many parts on the mt from jumping and not landing on the wheels, but never this type of noise. BTW the drive train seems to turn fine by hand no binding, but when under power it's too much noise, something is not right.
thanks for the help ~!

 

[nub]

Hard to say without hearing it but can you tell if it's coming from the front, middle or rear? Does the sound change with speed? Could be a bearing on the way out. Maybe the input coupler at the front or rear bulkhead slipped opening up the mesh of the differential pinion to diff. Maybe normal wear of the pinion to diff and could use a shim to tighten it up. Maybe a crack in a bulkhead that's hard to see that opens up under load widening the diff mesh making noise. Lack of grease on the diff to pinion gears in the bulkheads?

 

[freelosophy]

I lied, but I didn't mean to. There was no binding in the front or rear assemblies and the front drive train was fine. But the rear drive train was the problem. One of the four screws in the center diff holding the spur gear got loose and was rubbing a little. Problem fixed! Thanks for the tips !