I downloaded it but i cant seem to get it to run?

 

huh? I use VLC Media player to play most things. Maybe you don't have a MP4 media player? I wish I could configure the phone to record in a different format.

 

From your tranny, your shaft goes to a carrier bearing (center bearing, intermediate bearing or whatever you want to call it) and then angles down to your rear diff. Between this carrier bearing and the rear diff will be a rubber boot banded to your shaft. Under that boot you will find the "slip yoke". As you rig rises, falls and bounces around the distance between the rear diff and your carrier bearing changes. Your shaft back there is actually two separate pieces put together to allow the shaft length to extend and contract to prevent binding of your driveline and undue stresses on your u-joints. It is a splines connection, much like an axle shaft, but has a female end that is splined too. As your shaft moves back and forth, it moves the grease out of the spline grooves (not that there was much in there to begin with). There is no zerk fitting to grease it (go Ford!) so as the grooves dry out, you start to feel a clunk, or play, in the driveshaft. This will be most notable from a dead (or almost dead) stop and then you accelerate. It will feel like 2 or 3 clunks and like you have some slop in the driveline.

If you want to grease the slip yoke, drop the rear portion of the shaft, remove the banding and the boot (be careful not to damage the boot so you can use it again, I use zip ties to put it back on), clean all the old grease out of the joint, put some new grease in there (I use synthetic bearing grease), put it together and enjoy your "new" driveline. Always mark the orientation of parts so that you line them up exactly the way they were (the shaft is balance to go together a certain way) or you could end up with some unpleasant vibrations when you're done and a new problem to battle. I use tire or sidewalk chalk to draw lines across joints so that I get it back together the same way. The best way to drop the shaft and pull the slip yoke apart depends on the year of your truck. I don't remember the original write-up I used, but it didn't work so well for me, so you'll have to determine the best way to do it for you. For mine, I unbolted the u-joint at the rear differential and dropped the carrier bearing mount and was able to work it from there (mine is a 2003).

There are obviously other issues that could be causing your problem, but this is an inexpensive thing to do and is seems to plague a lot of us (I have to do this every couple of years) and is a lot cheaper than having somebody tear into a tranny or start pricing shafts and joint.

Just my .02

Best of luck!

 

Ahh, thanks for that.
This is most definately informative information as I have not yet lubed this part but it is now on my list to do but the slack doesn't seem to be there. It seems to be in the rear diff and the transfer case.
None the less I will be greasing this joint ASAP as I have a trip to Seattle the end of this month and I want this truck running at no less then 90%. Preferably 110% but I'll take what I can get without breaking the bank.
I will bookmark this post and get the yolk greased and change my rear diff fluid again, give it all a bit to work in and post again and let you guys know how it goes.
I will also be sure to mark my drive line very well as I don't like unsightly vibrations, neither does my U joints