No disrespect to powerRam50 but I would like to add a correction. I am probably late for your auction but hopefully the info will help someone out. After owning 5 Dodge D-50's and two Raiders. Most 4x4's except for one two wheel drive D-50 and rebuilding my share of these 5-speeds. First, there is absolutely no interchangeability of 86 and older trannies with 87 and newer. This is caused by two problems. First problem is that on 86 and older trannies the clutch is linkage driven while the 87 and newer use a hydraulic clutch. The second is internally, even though they do look the same internally the 87 and newer trannies have a thicker casing. Thus all the bearings and gears are a different thickness between the older and newer models. Other than a few screws and nuts and bolts, the only parts you can interchange between the old and the new are the brass synchro's. They are the same. Now, as far as the 2x and 4x difference, if both trannies are either the older or newer style then you can change the output shafts and end casing. Though this does require some major work, it is not difficult and can be done by anyone with decent mechanical knowledge and ability. Some factory manual photocopies from the local Dodge dealer will help also. So there you go. I hope that I have helped. One other thing. If you ever rebuild any of the manual trannies, make sure you write down your input shaft bearing number. There are 3 or 4 different ones and must be matched on replacement.