the two joints are the same. i don't understand why you have two different part #'s and one joint smaller. on my 89 4x4 the're interchangible. i'm 99% sure yours should be the same.

 

I talked to the dealership on this and they said that since I have the extended cab / Heavy duty axle - tow package etc etc. This required a stouter driveshaft. But they agreed that it normally a smaller one would have been used.

 

I hate it when this type of crap happens, especially when you're trying to be proactive in your maintenance and after the fix the car gets worse.

Just a thought, most driveshaft's are balanced with counter weights and before you take them apart you have to mark their relative position. Though since you'rs is a single piece I suppose this wouldn't apply.

 

Test

 

Is there a problem if when you spin the drive shaft sometimes both wheels will spin and other just one?

 

No problem at all. That meens you have an open diff. That is normal. Its not best for traction, but great for streets.

 

you have a heavy duty drive shaft and one larger u-joint to handle the load, the other u-joint is smaller and lighter duty, that kinda defeats the purpose of heavy duty. either the engineers at dodge who designed the dakota'sare dumb as a post or the dealership gave you incorrect info.check around at other parts places and see if the numbers are the same, if there not then check your shaft to see if any weights came off oralso check for grease or undercoating on the shaft to through it out of balance.

because it's heavy duty you may have a locker in the rear. raise the rear of the truck, spin one of the rear tires, if they spin opposite directions you have an open diff. if they spin the same direction you have a locker ( if you want to be sure call the dealership and give them the vin #, they can tell you if it has a locker) a bad locker could cause a shake but i'm not sure because i've never had one, i've heard of them exploding or seizing solid but not shaking.

 

Dealer decoded the Vin and the differential info came up as DRAS - Corporate 8.25 Rear Axle. Does this mean that I have a weak truck?

 

i have the same rear end and so does crazy4x4rt, and if we have not broke the 8.25 yet then it must be pretty tough, cuz i rag the hell out of mine and from the looks of it so does he, lol. mine is open too, it just means both tires wont spin all of the time, not so good fot traction at all so i have learned, just like crazy said.

 

Awesome! Thanks everyone for your advise!