Good morning everyone,


I have a 2007 Silverado Classic with 136k. 5.3L V8. Just yesterday, a new noise started.



If I put the transmission in drive (automatic), and go forward, there's a pulsating squeak whose frequency increases as the speed increases. At about 20mph, it appears to stop.



I verified it only happens in any of the forward gears, 1-D. It doesn't happen in reverse and if I'm rolling forward and put it in neutral, the squeak goes away. The noise starts as soon as the truck starts to move, with no throttle. If I add throttle, it appears to be a bit louder, again disappearing around 20mph or so.



For the hell of it, I greased the front driveshaft spline without success. Transmission fluid was changed at 100k miles, and there's no leaks and the dipstick is full, with the fluid appearing pink and clean.



There's no dirveability issues, with the trans shifting and operating like new.



Thanks for your help,


RickR90s

 

u-joints.


Sounds like u-joints.

 

I tend to think the same except I'm perplexed that it only happens in drive, going forward. There is no vibration.



Still, I'm going to have a driveshaft shop take a look.


Thank you much,



RickRs90

 

I had u-joints on my 90 do what you are describing. Would only squeek under load going forward. I found it odd at the time too.

 

I'm taking it in this morning. I'll reply back with the diagnosis.


RickR90s

 

just heard back from the technician. He says it's the rearmost u-joint. The front two are fine and he only recommends replacing the rear one since the front two rarely fail. So that's what I'll do for now.



thanks everyone!

 

Good deal!