I have a 23 ordered and it will be my first aluminum body. what's the consensus on under coating on these? Thanks Jim

 

Wool wax or fluid film

 

I did nothing to my 2020, live in rustbelt Indiana, have very little underbody rust.

 

I do a yearly application of wool wax to my 2018. First year took a really long time, since I thoroughly did inside the fame and outside. After that, I've done a quick powerwash to get any debris off, then a new application of woolwax to the outside of the frame, axles, etc. This year, (4th application), I did inside the frame again for good measure.

Woolwax/Fluid film do get washed off through the season, but even the areas with noticeable removal of the woolwax will still bead water and still have a super thin layer on them, so it's still providing protection. Everything looks new underneath, if not continuously goopy...

I primarily concentrate on the frame and suspension, but I do spray the aluminum body as well, including all the seams, up inside the boxsides, and in the box crossmembers.

 

I Krown every year (2017). No rust on body, but iron underneath has 3% or so rust showing. I happy with this as not bad. Rust Never Sleeps.

 

I yearly woolwax my frame (I use fluid film inside the frame), suspension, hitch and inside of chrome bumpers. I’ve done nothing to the aluminum parts.

Truck is a 2017 in Vermont.

 

Thanks guys, I've not heard of wool wax. I'll look it up!

 

Its like fluid film, both are lanolin based. Woolwax seems to hold up better in high wash areas.

Both are available in black or straw color.

 

I like boiled linseed oil. It darkens rust if you have any. It never gets super hard, but it dries to the touch. You won't get filthy working under your truck. Cheap and durable, It's kinda a forgotten rustproofing method.

 

I was doing some research the other day and found that these new trucks are made of high strength steel 70% more as compared to 30% of previous generations... which is why they dont rust as quickly.

surface rust isnt a real issue. I did look into undercoating some time ago, which many have said is a bad thing other then the spray on undercoating, because paint like undercoating might retain moisture which will actually speed up rust, the type your trying to stop.