just wondering if any of you guys spray wd-40 or anything similar on the underbody or susension before it snows? i was thinking of doing it so the salt has a harder time corroding

 

I dont, I feel it would catch to much dust/dirt, but I also drive some gravel daily

 

When the truck was 'spankin new with 125miles on it, I sprayed Eastwood Undercoating on the entire underneath. I used 3 cans of that stuff. I bought their pressurized spray gun to apply it. It's great stuff and is not a bulky asphalt undercoating you would generally see on most cars. That stuff is more for sound deadening than sealing. It looks very professional. I taped everything off that wasn't getting sprayed. I'll snap a few pics tomorrow for ya.
I did it on a completely dry day back in March. I rinsed the underneath off the day before so I didn't have much to wipe down.
I don't reccomend those undercoating spray cans you buy in Autozone. They peel off in layers.

 

WD-40 is a water displacement only, I would use rust check. It creeps into places you don't hit with the spray. I agree with dirtydog to clean under the truck first. I worked on mine last week and there was a pile of dirt resting on the lower inside of the front bumper an inch thick.

 

i usually just use our pressure washer every week or so on a day it's above freezing and just go to town on the big stuff underneath staying away from electronics, seals, and other such stuff. keeps it pretty clean.

 

I get mine undercoated at ziebart every year