Help! Nasty grinding noise!?!?!?

Timmys88Z · July 28, 2003

Ok, truck is '96 Z71 ext. cab 1500. 5.7 vortec, auto trans, ~70,000 miles everything original.

So, today on my way back home, just after getting off the freeway and accelerating... I get a real nasty loud grinding noise. What the hell? Let off the gas, goes away, back on the gas...grinding. #$&* Roll the windows down, turn the radio off. I hit a red light. When I start to go again there is nothing. I let off the gas, coast.... hit the gas again....GRIND. yadda yadda, it does this intermittenly for 3 more minutes until I get home. On the way home I tried putting it in neutral and reving it, everything normal there...so its only when its in gear. It did it in Drive, it did it in 3rd, and in my parking lot it did it a little in 1st as well, so it wasnt any gear in specific.

This happened just suddenly today for the first time ever. The drive train is all original. Is my trans dying? If so....this sucks, I aint got money for this $%&*.

Thanks,

Tim

Jersey Tahoe LT · July 28, 2003

Check the U-Joints on the drive shaft. Fron and Rear. I had the fronts go on me and they were loud and really painful the feel comming from the underside of my truck. Just get under there and try to turn and shake the drive shafts. For the rear shaft you may want to put it in neutral let it roll a little bit and then put the ebrake on. Then put it in park. All while the truck isn't running. That way you get all of the load off of the drive system and can move everything. I doubt that it is the tranny if it did it in all of the gears. Check the fluid just to be sure. If it isn't the drive shaft my next thought would be the diffs. Hope I headed you in the right direction.

Later,

Brandon

tmf6902 · July 28, 2003

I agree check the U joints. Was there any vibration with the noise???

Timmys88Z · July 29, 2003

Ok, I will check the U-joints and drive shaft tomorrow. I didnt think it was the diff cause I'm pretty sure it came from up front. I didnt notice any unusual vibration though.... I'll drive it again tomorrow and take it in.

I sure as hell hope it is as simple as the u-joints or even the diff, either will be a lot cheaper than the d**n tranny.

Thanks.

Timmys88Z · July 29, 2003

Also, another reason I am thinking something in the trans. is the grinding was a real loud and high pitched, buzz-saw like, sound. Like loud grinding gears....

Jersey Tahoe LT · July 29, 2003

Still Sounds like a U-Joint to me. I had a really loud Grinding sound. Good Luck man. Let us know how you make out.

Later,

Brandon

Tfin · July 29, 2003

I hope this isn't it, but what you're describing sounds exactly like what happened to mine:

I came up behind this guy doing 45mph, so I pull out to pass him. Tranny kicks into passing gear, I pass, and pull back into the lane. Then all of a sudden the rpms start climbing, but I have no acceleration. Just this grinding, and high pitch whine, buzzing sound. I let off the gas, rpm's drop and I give it some gas again. Same thing. So I drop it into 3rd and it engages, but with high rpms and a horrible sound.

I get it home, put it in park and turn it off. Then I restart and while in park I can hear the high pitch whining buzz. Put it in reverse and no engagement, but the same whine buzz sound. Neutral, same sound. Drive same sound and no engagement. But it would engage in 3rd, 2nd, and 1st.

Long story short, I got it to the dealer and come to find out it was my sunshell and planetary gears in the transmission, as well as two bad bands. Truck is an 02 Silverado with the 4.8L with only 20,000 miles at the time. Luckily it was fixed under warrenty, because the bill came out to $3,100!

So like I said, hopefully this doesn't turn out to be your problem, but what you descibed sounded awful similar. Good luck and let us know what you find out.

seadoons · July 29, 2003

Truck is an 02 Silverado with the 4.8L with only 20,000 miles at the time. Luckily it was fixed under warrenty, because the bill came out to $3,100!

Holy s**t!!! I'm glad I bought the extended warranty...now I just hope it pays for itself!!!! In your first description I really didn't know what to think. Then when you mentioned the high-pitched whining noise, to me that says something with the transmission. I had an '88 K-5 blazer, and I lost the tranny on it. It did the exact same thing as tfin described. Hope all works out for you.