My chain slipped, the part attached near the back wheel... "the two small wheels that rotates the chain I believe that it shifts the gears" it has fallen off and bent doing the time it was dangling. how much to replace or fix this attachment to the chain?

Dodge has had a problem in the mini vans for years with there transmissions Sliping in different gears,You will have to take it to a tranmission shop to get them to road test it to see whats wrong.

This happens when the back wheel is not aligned properly with the chain. As the wheel turns the chain is being pulled to one side causing it to slip to the next set of cogs. To solve the problem first you need to loosen the wheel by opening the 2 nuts on the axel. If the chain slips inwards towards the wheel you need to move the front part of the back wheel to the left from a view point behind the bike. If it slips outwards away from the wheel then you need to move the front of the back wheel to the right as viewed from behind the bike. When the chain and cogs of the rear wheel are lined up in a straight line the problem should be solved.

This happens when the back wheel is not lined up properly with the bicycle frame. Because the gears are not in a straight line with the chain it can slip. If it slips to the right, away from the wheel, then loosen the wheel and move the end of the wheel next the pedals slightly to the right as you stand behind the bike. If it slips to the left, in towards the wheel, then move the end of the wheel nearest to the pedals to the left. Once the wheel and the chain are in line it should stop changing on it's own.

By the "gear arm" I assume you mean that part of the rear derailer that the chain zig-zags through. This arm moves in two ways. It moves in and out (toward the wheel and away) as you move the shift lever - which is how it changes gears, by moving the chain onto different sprockets (gears). It also moves forward and back (toward the front and back of the bike) under spring pressure. This forward and back motion is necessary to take up the slack in the chain when you are using the smaller sprockets (the smaller the sprocket, the "higher" the gear). When the wheel has been removed, this arm moves forward (under spring pressure) as far as it can to take up all of the slack in the chain. All you have to do is grasp this lever and pull it toward the back of the bike, allowing the lever and the chain to pass behind the sprockets (gears) as you pull the wheel back into it's position. You can safely pull this arm forward and back at any time without doing any damage. One more tip-- I find it a little easier if you first put the shift lever in a "middle" gear position. Then when you pull the wheel into place, you should aim to put the chain on a middle sprocket. You don't have to hit the exact correct sprocket as you can simply lift the rear wheel and turn the pedals forward (after installing the wheel) and the chain will move to the correct sprocket corresponding to the setting on the shift lever.
Good luck! Please vote if you found this helpful. Al K

Hi, sounds like your front sprocket may be near toothless, which will make the chain slip if it's bad enough. You should be able to check it by eye, obviously check the rear as well. Also check the rear sprocket hub and wheel for any play. Lastly the vibration could be from tight spots in the chain, rotate the rear wheel & check the chain adjustment every 6 inches or so, if probs with sprocket or chain, they'll have to be replaced, hope this helps :)

sound like shift motor is slipping trying to rotate sector shaft to go in gear.

yes it will. You will have to adjust the gear shift cable so that it doesn't go past the 6th gear on the wheel (as you would've had a 7th gear) otherwise your chain will constantly slip off the wheel and jam up

Check the chain alignment may need to adjust shifter cable.

Check fluid level. Sounds like transfer case problem.