WD Hitch, Still a large amount of sway occasionally... help

[T3rry1]

Hey all, I purchased a (used) E2 truunion 10k WD hitch for my trailer, the trailer is relatively small, it's a aerolite cub hybrid, about 20ft closed up, 4000 lbs loaded up...

I installed this hitch by the book, followed all of the instructions, but on a recent trip i was changing lanes during a rainstorm and the trailer swayed quite heavily, it only happened a couple of times during the trip, and i could attribute some of it to rutty roads. The only other thing i could think is lack of tongue weight, would this effect it? i recently moved my batteries inside the trailer for security reasons, and to get 250 lbs off the tongue (4x 6v's, moved to just in front of the axle, under the table bench, vented outside.), but i just wanted to put out a feeler to see if there are any tricks people could suggest to ensure everything is set up as intended.

unfortunately at this moment the trailer is 5 hours from me, so i am just collecting info to try some tweaks next time i am pulling it (in a few weeks)

this is a pic of the wd hitch, just for reference, i dont have any pics of it installed on the trailer.

[ScottG]

A couple of pics of the setup might help us to figure out something.

[3oaks]

Without knowing more details, only guessing to causes.

Light tongue weight?
Speed? Towing in a rainstorm, maybe trailer tires hydroplaning?

[jayboogee]

I bought a similar weight distribution hitch, but decided, after spending $250 for the hitch, I might as well spend the extra $40 for the friction sway control. My suggestion would be to do the same. I pull a 31ft 4,700lb trailer with my F150.

[Dakota98]

Having moved the batteries, do you know what your tongue weight is now ?

How level are you when hooked up ?

On Edit: How did it tow prior to moving the batteries ???? :h