Is there any vibration associated with the grinding noise? Can you make the car make the noise with the car setting still by playing with engine rpm?
I've had a rattly one but it was as if it was the whole thing (!), not the cable in the tube. I can't imagine it is this in this case as it's most obvious when driving along, or it was with mine! Might be worth crabbing hold of the shifter when the noise starts (not to shift gears!) and possibly add some gentle side to side tension to see if that changes to noise. Worth checking that the shifter mechanism isn't touching anything at any time throughout the entire travel - the Lokar shifter isn't the daintiest thing and requires some space. Chris
Did your mechanic CAREFULLY inspect the outer rear axle bearings? That particular rear end didn't seem to have a very long life on those bearings and it would sound pretty much like what you describe. Be careful where you buy these bearings these days. I just bought a set of Timken bearings from NAPA and discovered they were made in China. I returned them and bought a set from Rock Auto that were made in the USA. Same bearings, different supplier. Now that's sad........
Probably doesn't apply here, but the wife bought new car, in the second week it developed a strange buzzy rattle. When I was driving it sounded like it was coming from behind the radio or glovebox. the wife swore it was coming from the driver's door. We took it in for some missed predelivery cleanup and asked them to find the rattle. It was the garage door opener on the sunvisor. At certain speed the battery would buzz in the case. Didn't do it in the old car.
Yes the noise can be recreated on a hoist. Problem is trying to locate it as it seems to travel through the whole drivelive and floorpan of the car.
Yes, when we did the rear we replaced them as well. Yeah, i noticed timkin has gone over seas lately. Very sad
yes there is a vibe associated with it, it can be felt in the floor pans and all the way up through the shifter. And no, car has to be rolling around 50 mph on the ground or in the air to be able to induce the noise. Doesnt seem related to engine rpm.
Firstinsteele, thanks for chiming in with those words of wisdom. Glad you took time out of your day to help spitball some possibilities with the group here. But i think the others have more to offer than you do, so feel free to move along and enjoy your day.
If the noise/vibration is not rpm related, that pretty well eliminates a broken/cracked flywheel. That would be more rpm related. You would feel it through each trans shift at a specific rpm range. It also usually eliminates anything exhaust related When you recreate the vibration in the air, is the rear axle supported (holding the car's weight), or is it hanging free? If its hanging free, that often eliminates anything chassis/suspension /drive line angle related. A speed related vibration is usually related to a balance issue, tires, wheels, driveshaft, or rear drums. An out of round tire, wheel, or drum could also cause the problem. As unfortunate as it is, you can no longer assume that new parts are good parts. I picked up a vibration at about 50 mph on my coupe this last summer, the new tires that were installed last year got out of balance. All we can figure was one of the wheel weights must have slipped. When the tires were 1st installed, the car was glass smooth, after 6 months or so, it got a minor vibration. The vibration got slightly worse, so I had the balance rechecked before we went on a long road trip. The car rides glass smooth again. A vibration through the floor pan and up through the seat is usually from the rear, you seldom feel those through the steering wheel. A vibration through the steering wheel is usually from the front, it may or may not be felt though the rest of the car. Gene
Is the floor pan touching any part of the rear suspension or driveline? Do you have any pictures of the underside of the car?
…….loose bolt somewhere…….? welcome to the HAMB…….with answers like that you will fit in here quite well…….. .
check the balance on the driveshaft? As you state it was sourced from speedway, I wonder if it was slightly tweeked in shipment, or a balance weight lost. This is not a Speedway bash, but shipping these days is somewhat fit or miss.
Question. Are you asking these repair shops to zero in on your problem or just telling them to rebuild what you think the problem is ?
Put the car on a hoist. Recreate the noise. Get a piece of solid round rod and start touching all the components of the car which the noise might be coming from. You will be able to isolate the problem a lot better. Did this with a bad transmission mount. A $7 dollar piece 3 days later after a 400 dollar repair on a Sunday 200 miles from home. The grinding was a bit worse. But I made it home with it still grinding.
I have had a lot of problems with out of balance drive shafts and flywheel/clutch assemblies. Oddly enough they all did the same thing you describe. Same speed, etc. Right now I have two flatheads with this problem. Since you don't have a standard transmission that pretty much narrows it down to the drive shaft, from your description. If I were me I would take the shaft to a drive line shop and have them check the balance and straightness.. I had a really bad problem with one shaft on a Dodge van due to an out of balance shaft and out of phase assembly. The first thing they asked me was "Where did you get the U joints? Was it NAPA?" That gave me a clue right away. A drive line vibration can cause noises that are almost impossible to diagnose.
Here is what I'm thinking. You may be looking in the wrong places for the noise. You said it "only occurs at a certain speed". If it was rpm related, it most likely would occur at that rpm in the lower gears/lower speeds as well. But it only occurs when the wheels are at a certain speed, and not a certain rpm. Not impossible, but maybe not likely. I'm wondering if it couldn't be a bad wheel bearing (front/rear). Many times a wheel bearing noise is only heard when at speed. I would put your car up on some good jack stands....... outside with lots of room in front. Then start the car and run it thru the gears while off the ground. Have someone walk around the car and try to pinpoint the noise. A two post lift would also work well. When elevated, if you get no noise, I would look at the front bearings.
This is kind of far out there but you might look at drive shaft slip yoke ingaugement 3/4 to One inch from being all the way in is about right
While you have it on a lift..disconnect and remove the driveshaft. That will eliminate the driveshaft and rearend from the equation. See if it still makes the noise then. How about removing the drive belts off the accessories off the front of the motor? Remove them too. But do one area at a time so you exclude a couple things from your test. Do the driveshaft first..if it still makes the noise..put it back in and do the belts.
If it is high frequency, my guess would be driveline related. The fact that it only happens in a "float" condition make me think it may be related to driveline angle. Have you checked the angles?
chassis ear is a great tool, used it many many times working automotive to pinpoint weird noises , vibrations and issues. I’ve had it where you, and 3 other mechanics swear it’s the right rear where the noise is coming from only to find out it’s from the transmission !! or left front suspension amd it’s a right lower ball joint but the noise for whatever reason is transferring down the line and being audible someplace else.
Last night I remembered something else. How are the spot welds at the floorpan? I had a noise that I could not track. Turned out 2/3's of the spot welds broke loose between trunk and interior behind the rear seat.
Yeah, I went through the same thing. Called around, tried to find US-made bearings, was assured that the Timkens one supplier had were US-made, so ordered them. I did a bit better than you, mine showed up and were Japanese SKF bearings in a Timken box.... Better than Chinese I suppose....
You said the noise is there when you put it on a lift. I assume you had it in drive at the time. So did it make the noise in all gears or just high? What you need to do is eliminate components and repeat the test. Remove one rear wheel, then the other. Remove the driveshaft but get a plug to seal it. Does it do it if you run it at speed (55) in second gear as well as high gear? As others have suggested, using a wooden dowel rod pressed against that little thingy on your ear often helps locate a problem. The thing that sticks in my mind is that you have to reach a certain wheel speed before the noise starts. Your trans output shaft ,driveshaft speed, your rear end, and your tires are the only things that have a relationship thats common when the noise starts. You have inspected the trans, so I'd look at the rear......especially the wheel bearings.
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