Is it safe to use WD hitch when raining?

Ron Gratz wrote:

thehippie wrote:
I noticed since my tow vehicle is rear wheel drive, the rear wheels would 'wiggle' more when raining. So when raining, is it advisable not to use WD hitch so the tongue weight of travel trailer would push more on the tow vehicle's rear wheels and be more stable?

This photo from your post in a different thread shows the hitch head is adjusted for maximum rearward tilt.
Depending on the number of chain links under tension, you might be removing too much load from the rear axle. If so, you should reduce the amount of load transfer.
But, as others have said, you should not eliminate load transfer completely.

A trip to the scales will tell you how much load is being transferred. You'll need to make three weighings:
1) TV front and rear axle loads with TT unhitched and WDH in the TV's receiver,
2) TV front and rear and TT axle loads with TT hitched but no WD applied,
3) TV front and rear and TT axle loads with TT hitched and with WD applied.
Passenger and cargo loading of the TV and TT should be the same for all three weighings.

Post the scales numbers and we can assist with interpretation.

Since you are using a friction bar sway control, you might need to apply slightly more steering input in low-traction conditions.
But, I would not expect the friction bar to cause the rear-end "wiggle".

Ron