I am willing to bet a case of beer that installing a WD hitch that can put more weight back on the front axle will solve your problem. In my previous responses I was under the assumption you originally had a WD hitch but I evidently mis-read your first post.
On another note, you say your tongue weight is 900lbs. That was probably overloading your receiver hitch rating by almost double, which I believe in Dodge trucks of that year was only rated for 500lb in weight carrying mode. It was rated for 1000lbs in weight distribution mode.
Barney
