Ok.. Fellas need some ideas. This forum always great advice.



My truck through codes for oxygen sensors -front and low catalyst performance. The truck is a 99 Silverado Z-71 ECSB so it has some age and tough miles. Cats started to rattle. OK ... Bad cat. Replace same.



Now it has another creak while in motion. the sound is not coming from the motor, I replaced the u-joints 6-8 months ago.



Tranny was replaced 2 months ago with FLT Level 5.

Need some ideas on what to look for. The truck was out of service for 6 weeks waiting on tranny, the driveshaft was int he ned of truck the whole time, could u-joints again be bad.



The noise does increase with truck speed, then goes away. Comes back at lower speeds, and reverse.



The front U-joint has grease fitting, I greased it today. The rear was a last minute resort with no grease fitting from Advance Auto..



Any thoughts?



Thanks!!!

 

On a level surface, mash your parking brake and chock your tires. put your truck in neutral and crawl under it, try to rotate your driveshaft back and forth if there is play, any play then its time to replace 'em. if you try to check with the truck in park there is a pretty good chance that the driveshaft will be in a bind and you wont be able to notice any play. u joints with grease fittings are hollow, they have cavities that run through the joint for the grease that weakens them, i would rather have the solid non grease able u joints. have you checked your engine/trans mounts? exhaust clearance? maybe a squeaky shock? just throwin out ideas.

 

I suspect the u-joints. But will double check everything else. Shocks were replaced a few years ago with Bilstein HD's..