The numbers look good.
- Keeping the front axle the same is ideal though not common. A couple hundred pounds off isn't a big deal.
- You are at 10.9% hitch weight.... 640/(640+5220)= 10.9%. I like 12-15% but it should be fine. Below 10% is where it really starts to get sketchy.
Since you didn't mention it, I assume the back of the truck isn't squatting noticeably when you hook up.
The one item, that needs adjustment. The camper should be level when hooked up. An inch low isn't a big deal but since you noticed it, I'm assuming it's a few inches low. Your WDH should have adjustments so you can raise/lower the height of the ball. Take some measurements while hooked up to see if how much you need to raise the ball. A side effect of this is you will likely need to adjust the WDH again as raising the hitch will reduce the tension on the bars if everything else is kept the same. If it's the chain style, you may just need to raise it a link or two. If it's the L-bracket style, you probably need to raise it a bolt hole or two. Check the hitch manual as it should describe how to adjust.
Looking your calculation; - "You are at 10.9% hitch weight.... 640/(640+5220)= 10.9%. I like 12-15% but it should be fine."
Trying to understand what measurement(s) resulted in the "640"?
Hitched truck - Unhitched Truck = Hitch weight
(4000+3700) - (4000+3060) = 640
Got it thanks, Had a senior moment there. 🙄
