2006 dodge grand caravan 38000 mi. grinding noise

You probably have a bad right side C V shaft. The shaft has a spline joint in the middle; over time water gets inside and rusts the splines causing it to slip(makes grinding noise), and it will not turn the wheel, causing the wheel speed sensor to cause the traction light to illuminate. Replace the C V shaft (reman ones are really cheap)

maybe some thing in the brakes

constant or while braking? checks brakes first if no issues seen (evidence of grinding) then you have a wheel bearing going bad.

there is a tbi on dodge caravan and grand caravan for the front and rear brakes locking up . it is a recall if you are under 60,000 miles

Was the parking brake on? Sitting that long it may be hanging
up a little. The cable may have a little rust on it and it's not releasing
all the way. If thats the case you may be able to feel the back
wheels after driving a little and they will feel hot or you may even
smell the brake shoes wearing.

have you replaced the front and rear brake pads (for older vehicles, rear wheels use brake shoes instead of brake pads). if yes, check your calipers. completely remove it from your tire and have it cleaned.
if the problem still persists, then its time to replace your hydrovac

It could well be in need of new brake pads however this would be noticable more when you apply the brakes if the sound is in the rear its not the front brakes it could also be your wheel hub bearings are past there used by date its a serious problem and needs attension right away

what type of noise squeal or growl or grinding if it is grinding or growling i would look to wheel bearings if it is a squeal it is the material the pads are made from

There are 2 bolts on the "inside" on the caliper towards the bottom they use an allen wrench socket.

does the van shake or vibrate? does the van have tires on it ?start by switching the left rear with the right rear test drive and listen for soun if no sound then the tire has a bad steel belt replace tire if the sound is still present. jack up van and spin tire if no sound is heard replace wheel bearing and if there is still a sound look into brake drum for possible springs or clips that may have fallen into drum causing noise but i would say its more than likely the rear wheel bearing to change that u must buy a new bearing and follow instructions on replacing good