Hi all, I recently got a 73 d200 with extended cab. I'm fairly new to trucks.

It makes a clanking sound when dropped in gear, which sounds to me like a U joint. I crawled underneath expecting to see a regular driveshaft, but this one has a front then a center carrier then another in the back.

Can you all tell me what's involved if I want to service/refresh the entire thing -- from trans to the rear end? How many U joints are in there?

Do people ever convert to a single long driveshaft and do away with the center carrier? I'm sure there's a good reason they made 2 piece, I just don't know what it is.

Thanks from a truck newbie.

Should be 3 joints. The carrier bearing is pressed on. Might just pull it and take it to a driveshaft shop is you don't have a press.
I wouldn't replace it with a single shaft. Would change the pinion angle relationship.

You should be able to see and count the joints for yourself. As for a one piece shaft? You can only make them so long.

Plus the 2 piece driveshaft keeps more of the driveshaft tucked up for better clearance.

What??? do his own research...

In addition to the reasons already mentioned, if the truck is an automatic it is a short tail trans and does not have a slip yoke at the back of the trans. Instead the u joint attaches to a yoke bolted on the end of the trans output shaft.
If switched to one piece, this would leave no room for the driveshaft to move with the rear end when the suspension moves going up and down when driving. It would require you changing trans to the car type long tail shaft and slip yoke to use one piece.

FYI, make damn sure you mark the phasing of how the two pieces of the drive shaft now are in relation to one another before taking it apart. Put it back together the same way it came out, or you might have one hell of a vibration.