Technical Weird grinding noise???

It might be the crazy in me but in these instances I put the rear end up on jack stands (HAMB approved cement blocks of course ) so the rear is free to spin, start her up and run it till it makes the noise. I then slip it into neutral and kill the engine, allowing the rear end to keep rotating. That test takes the engine out of the equation.

 

Following, my Merc does the same thing. As soon as you go off the gas, there's a faint grinding noise. I too have the Lokar Shifter, but it could be a coincidence. I always thought it could be pinion angle issue, but that was just my o-pinion. I'll let myself out.

 

If it was my car, I'd dis***emble the U-joints despite the fact that they are supposed to be new.

 

While he’s at it he might as well dis***emble the rest of the car maybe if he starts replacing parts at the front and ends up at the rear the noise will go away

 

Probably way off base (and my rocker) but could you have a warped brake drum intermittently hitting the backing plate? Rotating things can expand and/or change shape at certain speeds. I also second the statement that SKF makes superior quality bearings. I still have my doubts about that driveshaft. Of late, Speedway products are somewhat suspect, in my opinion.

 

Yea, like others have said, - disconnect the driveshaft and take it out for a test drive……………….

 

Kinda rude for a FNG

 

So, has the noise disappeared on its own?

 

It's a natural tendency to automatically eliminate new parts as a possible cause, but there is a reason they put warranties on things.

 

Ben

 

Noisy Alternator's my guess, or water pump, power steering pump. Put a big screwdriver in your ear and start touching and listening. For all the old and dumb "Handle in your ear, tip on the engine". Thank You, love getting comments from "All Y'all" lets go.

 

I had a similar issue.....drove me crazy. One day under my truck for a totally unrelated issue, I leaned on the exhaust to help myself up and voila....saw a crack open up on one of the exhaust hangers. Couldn’t see it with a visual inspection. Only at a certain speed when the resonance was right it would sound like a grinding noise.... Welded up the crack and my noise was gone! Hope you find your issue.....

 

OUCH.

 

er...HANDEL!
Or handle, of chosen dri--vair!

 

Only the handle....

 

Hey just punch out both eardrums an you won't worry about the sound anymore

 

Well, for what it's worth, there is only one thing left that I can think of. Ring and pinion bearing setup.
Setting up a rear end is a delicate process and requires a lot of knowledge about gear mesh and pre-load torque specifications. Does your mechanic have adequate experience with this? I know for a fact that improper setup can cause exactly the problem you describe. I ***ume the pinion seal was replaced?
If he didn't install the U joint flange properly it would change the settings and could cause damage.
It's one of those things you don't just put the nut on and tighten it until the rattle wrench stops turning.

 

As my mom was known to say . . .

"Never stick anything in your ear except your elbow."

 

I've got this one figured out, the radio quit working!!!!! Get a new radio, and while you're at it, get some new boom boom speakers, viola! You'll never hear the grinding noise again!!

 

Volume! That new radio needs to have a lot of volume. You will need to be able to turn the radio up and the grinding noise gets louder!

 

Make sure the volume will go to eleven.

 

The only thing that has me worried is a "junior hot rodder...." with an automatic transmission.

 

I like to use a wooden dowel to "listen" for noises. If it gets ****ed into the belts, it will break and not harm anything... at least in theory. Heater hoses or old garden hose is good too.