My 1994 dodge dakota, when i have any weight in the bed of the truck the truck will be in a strain and will not move, the whells just spended.

You're saying that if you put weight in the bed, the back tires just sit and spin but the truck won't move? I've never heard of that problem but it is very interesting. I will do some research and get back to you, but first I need a little more information. What engine and transmission combination do you have? .

Another part of the question would be what condition are your tires in and what does the area where the truck is sitting look like? Is it grass, mud, wet pavement of any kind? If the tires are spinning, but you're not going anywhere, the clutch and tranny are good if it's manual and the trans is good if it's automatic which brings you down to the tires.