Strange sound

[BRONCO]

Hi folks. I have a 96 LT4 CE GS with 96,012 miles on it. I'm almost afraid to ask this question, but, when I am taking off from a full stop like at a traffic light, you know, normal driving, I hear what sounds like a cracking sound that seems to be coming from the rear wheels. It seems to happen only when initially engaging the clutch to start forward movement. I've had my baby for a few years now with no problems. I've driven it almost every day. All of this time I've heard this sound (only at take-off). I've just sort of ignored it thinking it was something unique to the LT4. Does anybody out there know what I'm talking about? If so, please let me know what this is.

 

[Vettelt193]

sounds like the u-joints to me.... there are 6 of them total, but the 'main' 2 usually don't go. just the 4 that connect up the half-shafts. once one goes, it is best just to replace all 4

the easiest test is to jack the car up, leave the car in gear, and check for play in the rear tires (rotate them back and forth)

 

[Tuna]

I'll second the u-joint analysis. This sort of sound is just what failing u-joints sound like.
Besides 90K miles is about when they start failing anyway.

While you're having the u-joints checked out, don't forget to check the hub carriers (wheel bearings). They start to go bad around the same time.

 

[wx briefer]

I used to hear a 'creaking' sound from the rear each time I initially started forward or backward. I had the occasion to remove my transmission (clutch fork bolt needed to be retightened) at about 90k? miles. I used the Zip products beam plates and used liquid nails on the contact points of the C beam at the transmission and rearend. Lo and behold, the creaking went away. Even though the u-joints were still good, I replaced them also. I would suspect it is simply the noise of the C beam on the tranny or rearend if you have no other indications of bad u-joints. I don't know what GM used on the C beam contact points originally but it looks just like the liquid nails.