What does it mean when I have metallic shavings on sensors of an 06 dodge caravan and van won't go forward or reverse

run the fault codes
indicates a torque converter clutch servo/ solenoid problem

If engine RPM goes up when you try to go forward but vehicle won't move the forward gears is not engaging in transmission. Could be caused by several things. Check transmission fluid both level and condition mostly condition. Get a white paper towel whip dipstick on paper towel and look for any gray in fluid if transmission fluid is gray you have metal shavings in fluid. Most likely need a new or rebuilt transmission.

If it only happens when transitioning between forward and reverse it may be your CV joint. You may also hear/feel sounds when turning to left or right.

Not good if it makes a grinding noise. Needs a tech or replacement as something most likely has come loose inside the transmission.

may have s blown head gasket. Does the car smoke? Check for water in the oil.

1. Yes the 3.3 and the 3.8 are the same bolt pattern. But the gear ratio in the differential might be different.

2. Did you replace the filter and put it back together? Does it do the same thing after you changed the filter? If it was an electrical issue with speed sensors or the solenoid pack, reverse would still work.

The correct fluid to put in a 1997 van is (ATF-3). Sounds like you need to make adjustment on both the forward and reverse bands of the transmission to correct your problem. The kickdown band (front) forward is located at the top (outside) of the transaxle near the front. To adjust the band,loosen the lock nut approximately 5 turns. With the lock nut loose the adjusting screw should turn freely in case. Tighten the adjustment screw with an inch lb. torque wrench to 72 in-lbs. Then back the screw out 2 1/4 turns, hold the screw in place and tighten the lock nut to 35 ft-lbs. Then after removeing the transmission pan and filter the low-reverse band is located next to the valve body. Loosen the lock nut 5 turns so the adjustment screw is free. Turn the adjustment screw in to 41 in-lbs, then back the screw out 3 1/2 turns. Hold the adjustment screw and tighten the lock nut 10 ft-lbs. Install transmission pan/with gasket and refill transaxle to proper level. Test drive van. Be safe and block the rear wheels before you raise the van and try to work under it. Hope this will help you.

because they only made 3.8 for that year

have the system tested for a trans related trouble code, u may have a defective OD speed sensor.

The shift soleniod is the most logical answer or the shifter cable has to be adjsuted.
I do not think the gears are an issiue. Is you fliud clean ? Does the fuild smell burnt or dark in color.
Is there metal shaving in the fluid. ?
If any of the above condition exist then you should take the vehicle in for service .