97 blazer driveshaft noise

Everytime I put the truck in drive I hear a noise from under the truck.
Is it hard to pull the driveshaft and change the universal joints.
thanks for any help.

I am sure that someone will pipe up and corect me, but -

I think the U-joints are held in with injected nylon. Replacement would require a vice, blowtorch and the replacement joints/rebuild kit. One locks the shaft into the vice, heats the joint with the torch until the nylon melts out from the caps and then you can extract the old U-joint's bearing caps. Repeat as necessary to get all of the caps out, the needle bearings removed and the trunnion free. Rebuilding is the reverse of removal for the most part, but your kit will come with detailed instructions on how to deal with it. Instead of melting nylon back into the caps, one would use snap rings supplied in the kit and slightly different bearing caps, also supplied.

However, before you go crazy doing this, get under the truck and with the tranny in park and the parking brake applied, grasp and twist the shaft in your hands. If there is a clunk and alot of play, then I would consider replacement of the U-joints. (There will always be play, but excesive play is what to look for. My joints are healthy and there is about 1/16th of an inch of play from the transmission parking pawl.) Otherwise, your problem may be elsewhere. Are you engaging the tranny in gear when the engine is still in cold, high idle? This will make things engage with a spirited thump. Also, have you checked your tranny mount at the crossmember to make sure it is not sheared through with age - this will make a clunk too when backing the truck up and changing into forwards gears, etc. Check this by inserting a beefy screwdriver between the frame crossmember and the plate the tranny is bolted to. Pry up on it good and firm. If you can see light through a crack between the tranny mount and the frame, it's shot and more likely your problem if the shaft is nice and tight.

that is half correct, some s 10's have 'funky' (intermeidet shaft) drive shafts and some have regular good ol fashion shafts, if your like me and luckly have an old one do it like it use to be done, other wise, ive never done a 'funky' one so i cannot help ya but wolfox seams with the book on it so to speak

Remove the 4 bolts on the drive shaft u-joint at the rear pinion and pry slightly forward, rear drops out and then pull the shaft out of the trans (2wd) or xfer case (4wd). Then do the above or I always take to the shop and for under $100 they install both new and spin balance so no vibration - costs a few bucks but well worth it if you crank it up to 75-80 on the highway as some of us do.

I am sure that someone will pipe up and corect me, but -

I think the U-joints are held in with injected nylon. Replacement would require a vice, blowtorch and the replacement joints/rebuild kit. One locks the shaft into the vice, heats the joint with the torch until the nylon melts out from the caps and then you can extract the old U-joint's bearing caps......

This is the way to do it DIY style.

I helped my nieghbor do his '99 S10 P/U. We both used our handy dandy propane torches to melt the nylon out (pops out like a giant ZIT when heated to the proper temp) took about 10 minutes (and a beer each u joint) with two torches to reach the proper heat.
New units used snap rings to retain the cups.

Thanks I'll try to get under there and pry on the mounts.