C4. Torque converter fluid brown, Trans Good

[Early74Bronco]

Drained the torque converter and it was brown and smelled horribly burnt. Then drained the transmission fluid and she looked beautiful. What’s my issue?
Thanks!

 

[Rightpace]

Going to need more information.
Has the transmission been operating?
Did you add fluid to the transmission?
Details...

 

[Early74Bronco]

Transmission is working great, haven’t added fluid in a long time. Only drained it because I’m getting the motor rebuilt.

 

[Rustytruck]

my guess mismatched gearing with large tires or heavy towing overheating the converter maybe not enough use of low range in the transfer case.