Dodge

I own a 1998 dodge grand caravan with 223,000 miles and a 3.8 liter engine. while driving on the highway, i started to go down a steep hill and the steering wheel started to shake hard and irregular. i thought the wheel was falling off. the next day a chrysler mechanic looked at it and said the wheels and all front end suspension components looked nice and he could not duplicate the problem. i decided to drive the 90 miles home. 10 miles into it, the shaking started again. i noticed that it only does it when faster than ~30 mph and when decelerating. applying brakes does not affect it. i drove it home. can someone tell me what this is? i am thinking differential pin after research but it sounds like that happens during acceleration and is more of a whine.

Without being able to drive it ,its hard to tell,you might want to have the mounts checked on it and also have the transmission checked it may not be down shifting and trying to stay in another gear,that will cause it to shake like that ,i had one that was trying to stay in lock up mode and that caused it to shake real bad,have a transmission shop test drive it,this could be a bad axle or a bad motor mount or transmission mount and it may be binding it up ,good luck with it.,,ps you could also have a bad tire on it,that will cause that too happen also,have it checked again,they should be able to find it,good luck.