I have a 1999 gmc jimmy 2door SL 4wd. It has 108k miles. within the last 3k miles I have noticed that when I am reversing out of say, a parking spot, it will squeak, like a eeee ooo eee ooo eee ooo... best I can do on here lol. but basically its not a steady pitch, it goes up and down. I have replaced my ebrake shoes, brake pads, rotors, and have greased the pad guides with silicone brake pad grease. the noise has not changed at all. I can try and put a video on youtube of this noise and add a link when I get time. Anyone have any ideas what else could make a squeak, from the rear, only in reverse if its not the brakes? the squeak gets much more pronounced and apparent when I push on the gas in reverse as opposed to just rolling in reverse, however it never actually goes away. so, as I push the gas, the rear end of the vehicle lifts up due to torque and I start moving and the squeak is significantly more obvious, once I let off the gas it is still there but about half as loud.

any ideas on where to check next would be greatly appreciated.

 

okay I made a video of the noise that my truck is making, it's not the best, but its all I have. This noise only happens when I'm in Reverse. It gets louder when I'm giving it gas but when I start coasting in Reverse its a lot quieter but it never goes away. I thought it was my brakes, but I've installed new emergency brake shoes as well as brake pads and rotors I've cleaned my calipers and properly greased them. now I am clueless of what to check next

any tips or information would be greatly appreciated

 

I think it would be your U-Joints. Mine made the same exact noise when they were seizing up. I would replace those if I were you, I bet the sound will stop!

 

i will check them out. i think i remember using and automotive stethoscope to listen to the ujoint while it was on jackstands with the transmission in reverse. i felt like the noise was coming from near the wheels, but maybe i overlooked something. is it possible that i could spray some grease or something on the ujoint while its spinning to see if the noise changes?

 

well i just sprayed some lithium grease all over the ujoints and the noise is gone. sounds like they are bad. i will look into replacing them and post back here. thanks alot for the tip im sure this will fix it!

 

Awesome, I'm glad you got it narrowed down. If they are factory joints, you will need a good propane/map torch to heat them up, gm injected nylon to hold them in. Took me 2 hours to replace my factory joints. I tell you what though, you will notice a difference when you are done!