Almost every time I take my foot off of the brake pedal I hear(feel) a thud. At times its louder than others. What is the issue and the fix? It is a 2002 RCSB I bought a couple months back. It has the 5.3 .

 

I'd start looking at the brakes themselves maybe. Check the calipers and pads, pull the drums if you have them to see what the shoes look like.

Shake the rest of the truck down too, bearings, tie rods, ball joints etc etc.

 

02 shouldnt have drums..... Saw one with a similar issue the pushrod was hanging in the booster... Booster fixed it, just something to check, i had to have someone else push the pedal down while i looked up underneath to see the pedal popping back up, wasnt much but enough to cause a thud the last bit of pedal travel!!! Have seen sticking caliper slides cause a similar issue as well...

 

I do not feel the thud in the pedal,it is a small thud throughout the truck. I've done some reading and I've also read about driveshaft "play" which is a common problem. Could this be the problem? How do I check if its the drive shaft. I'm not a shade tree mechanic so I'm not savy with auto repairs or knowledge.

 

You can get under the truck and shake the driveshafts. They shouldn't move about or clunk.

 

i have the same issue in my 08, the way I have been getting rid of it is pulling the drive shaft out cleaning the splines and coating then with heavy grease. its not a 100% fix but it does help on my truck.

 

Like 97low said, it's the slipyoke sticking on the tailshaft. Remove propeller shaft, thoroughly clean the splines inside of the slipyoke with a brush and solvent. You can also support the trans and remove the tailshaft housing to clean the splines on the tailshaft. Apply spline lube (GM #19257121 or equivalent) to the splines and reinstall the propeller shaft. This is only for 2WD vehicles, 4WD do not get this this treatment. In a case of extreme slipyoke wear there is a nickel-plated replacement yoke available too.

Google "Driveline Clunk". It feels like brakes or even the rear end sliding on the leafs but it's just the slipyoke. This can be confirmed by recording it with a GoPro at 120FPS.