1997 GMC Sierra Intermittant hard shift btwn 1-2, 1870 code

The rebuild vs recycled trans is up to you and what the cost is. Junk yards usually guarntee their trans to work. The only problem is the electrical connection that they take. They have to be the same otherwise you can run into problems trying to get your trans to work right. When it is rebuilt, every seal and clutch plate are replaced along with the torque converter. And parts that are found bad like planetary gear sets arealso replced usually with new but not always. Also if you get a trans form a junkyard and it doesn't work, then you have to pull it out and get another one. It's just if you decide to do the work yourself of replacing the trans or not.