Thnaks for the heads up on the t-case EIZNEKCM.. are you sure thay are different?? and do you have any other words of wisdom?? tricks those of us considering this should thik about.. J

 

I know for a fact that the 6-speed and the new auto have different splines. I bought an auto t-case on ebay for $100,and spent over an hour trying to line the splines up before I realized they were different. (I had to "rebuild" the one from the salvage yard package. It had a leak that I could not find and I ran it out of fluid. The chain stretched and started slipping.) I split the case and took the good chain and gears and the back half and mated it to the front half of mine.
I am not sure about the 5-speed and the old auto. It seems like I read somewhere on this site about it. You may want to ask on the tranny forum.
Another thing I just remembered. If you change the T-case you will need the drive shafts from the newer truck(yokes are different) I cut and rewelded the original shafts to the new shafts. I can give you more info if you don't understand what I mean.
You may have to do some fab work on the driveshafts anyway because of the different lengths of the trannies.
This is really not that hard of a swap, if you get all of the required parts. I would try to get everything before begining. Its a real bummer to get close to being done and then have to stop to get something from the junk yard.