No only is in not towable, per Toyota, it weighs too much for your Navion. You are limited to 4200 lbs (yes, the hitch says 5000 lbs but your tow limit is less). Suggest you think smaller for a toad.
True, not towable as mfg by Toyota.
However Remco (link earlier in this topic) may have a lube pump for the transmission, just need to verify the model # of transmission. See Remco website for details.
This doesn't change the towing capacity of the RV though.
I towed a 2012 Tacoma 2WD with the addition of the Remco drive shaft release for 4 years, worked great! It's about $1000. I traded the Tacoma in with it still installed when i upgraded to the 2019 Chevy Colorado.