Not a happy TH350 trans - need help trouble shooting how bad.

[74k20]

74 k20, original stock 350, th350, np203, 255 85 16 tires (aprx 33"), 4:09 gearing.  Mild SB400 in shop being built for transplant maybe this winter.

TH350 issues.  Towing power has always sucked and blamed on my low hp year motor.

While towing my camp trailer over the weekend, it was low on HP and occasionally did a quick grind noise.  Smelled and felt HOT.  New radiator so assume trans cooler is fine, motor temp was fine, only 60 deg day, no clutch type slipping.  Also heard a rattle once and awhile, like a floating loose piece sound.  Then it started to shutter upon take off, but stopped once rolling a few feet.  Made it home, trans fluid smelled burnt, level was fine, color not perfect pink but ok.

I've never trouble shot a trans.  Is this a major catastrophic type symptom, or could there be a possible pan drop fix scenario?

[zieg85]

Sounds like a catastrophic failure in the making unfortunately.  My TH400 is making some real strange sounds itself so I know it is just a matter of time.

[Lt.Del]

i never, never, never pull anything without an external trans cooler.  First thing i do when buying a truck, is throw an external trans cooler on.  Heat kills transmissions--and these puppies create a lot of heat when towing.