Every now and then when I put my truck in reverse, I get a clanking noise underneath... And my driveway is uphill a little and when I throw it in park and take my foot off the brake, it rolls about 3 to 5 inches backwards. Does this sound like I'm in need of a new tranny or is there a easier fix?

 

sounds like you got slack in the drive train u are fine it comes with milage

 

Do you know if this would cause the vibration @ 45-50mph???

 

u could have a ujoint trying to go or if its in the front end then it might be a tire or needs an alignment

 

I thought it was the tires too at first. When I bought the truck the tires weren't rotated very well, so I bought four new M/T tires w/ alignment and it did ride alot better, but it still shakes at 45-50 mph.