Where did you get your info on ATF having a lot of detergent in it? It is basically a modified hydraulic oil.
Here is the chemistry for an ATF such as Dexron III:
(Average additive concentration by wt.% taken from seven (7) different additive packages)
Phosphorous - 0.025% from AW additive
Zinc - 0.0008% AW additive, anti-oxidant as ZDDP
Nitrogen - 0.1% Dispersant and Friction Modifiers
Boron - 0.016% Detergent and AW additive
Calcium - 0.02% Detergent, tbn base chemistry, corrosion inhibitor.
Magnesium - < 0.0005% Detergent and base chemistry
Sulfur - < 0.55% AW
AntiFoamant - 0.005%
The unseen additives in ATF are anti-oxidants, dispersants, special friction modifiers, anti-foam, anti-rust agents, seal swell additives, anti-corrosion additives, and metal inhibitors for copper and aluminum.
Saying that it is high in detergents when comparing it to regular motor oil is misleading. Motor oil needs detergents to help in cleaning out the hydrocarbons and combustion by-products such as gasoline produced from blow-by in the engine. Transmissions are a sealed unit and do not produce hydrocarbons and thus need less detergents than motor oils. They use more friction type modifiers to assist in keeping the wear and tear on needle bearings, sun gears, etc. to a minimum. That is why when a person tears down a transmission, the internals are clean compared to an engine internals. No hydrocarbons to attach itself to moving parts. What you posted is an old wives tale from many years ago before we were much more informed about ATF versus engine oil. You would be better off just flushing out the engine with straight 5w motor oil which has the detergents that your engine needs versus ATF which is basically 5w without the detergents.

 

Have you looked here????? https://dodgeforum.com/forum/1st-gen...-pressure.html

Replace your PCV valve as well and check your engine breather hose is properly attached to the air hat. Also check for leaking vacuum lines and/or a cracked vacuum tank under the crowl.