1994SEV6 Posted January 9, 2012 Share Posted January 9, 2012 (edited) My truck seems to have developed a high pitched whistling at ~highway speeds. This isn't the whistling noise from the M/T in any gear but 4th. I know what that is, and this is different. If I just heard the noise by itself, I would think it was a spaceshuttle or a generator powering down. This morning, I was going about 70mph when I noticed it. I didn't have the radio on, the heat was off, I put it in Neutral, and I heard this really high whine. As a slowed down, it got slightly deeper and deeper until it disappeared around 15mph. If I listen carefully, I can hear it "power up" through the gears. This just started happening today. Since yesterday I: Filled my trans up with 5qts of Redline Mt90. This was the first time I drove it since I filled it up. And I put my shift boot on properly. I put the big silver metal plate on, and the black rubber thing and the shift boot. I bolted them down. I was thinking that the air flow through the boot might be getting pushed through a small opening and causing the whistling? This is just me hoping for it to be something simple. I made some videos but I'm not sure if the camera picked up the sounds. Oh yeah. I tried to listen for the location, but I kept getting confused. I could have SWORN it was coming from the rear, but then I convinced myself that it was coming from the front left So it got louder. I'm pretty mad. I made a good video this time. I move the microphone from the floor to my mouth to say my speed. It's actually really loud. It completely follows the speed of the rear end. It doesn't match my RPMs, gear, or anything else. Caution: it's loud. Turn down your speakers. http://www.youtube.com/watch?v=OwD6gTUEKN4 Edited January 10, 2012 by 1994SEV6 Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 10, 2012 Author Share Posted January 10, 2012 can someone listen to my whining please? I got videos and everything. Get cheese. Link to comment Share on other sites More sharing options...
krmiller07 Posted January 10, 2012 Share Posted January 10, 2012 can someone listen to my whining please? I got videos and everything. Get cheese. Does it continue to make this noise when the clutch is disengaged or pedal to the floor? Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 10, 2012 Author Share Posted January 10, 2012 Does it continue to make this noise when the clutch is disengaged or pedal to the floor? I don't think I know that question specifically, but nothing changes it. It does it in neutral. And one time I was coasting with the shifter in 4th and the pedal all the way to the floor and it still made the noise. I think that's what you want to know. But I wasn't in N with the clutch depressed. Link to comment Share on other sites More sharing options...
andreus009 Posted January 10, 2012 Share Posted January 10, 2012 Could try jacking it up in the rear with both wheels off the ground and "drive" it to spin the wheel(s) it to see if you hear a similar sound coming from the rear without actually moving. Obviously, safety first...solid jack stands under axle and front wheels chocked. Are you in 2WD or 4WD when you hear the noise? Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 10, 2012 Author Share Posted January 10, 2012 (edited) Could try jacking it up in the rear with both wheels off the ground and "drive" it to spin the wheel(s) it to see if you hear a similar sound coming from the rear without actually moving. Obviously, safety first...solid jack stands under axle and front wheels chocked. Are you in 2WD or 4WD when you hear the noise? 2wd always. Ok. that sounds like it might be a reasonable idea. Is that realistically safe? On my bike, if I pedal the rear wheel, it creates centrigufal force that vibrates everything. That's not even going fast. If I jack it up and get the wheels up to ~40mph, is it going to stay on the jack stands? Might it create insane vibrations and forces because the road isn't there to absorb them? Edited January 10, 2012 by 1994SEV6 Link to comment Share on other sites More sharing options...
krmiller07 Posted January 10, 2012 Share Posted January 10, 2012 (edited) I don't think I know that question specifically, but nothing changes it. It does it in neutral. And one time I was coasting with the shifter in 4th and the pedal all the way to the floor and it still made the noise. I think that's what you want to know. But I wasn't in N with the clutch depressed. Ok, then that can partially rule out the transmission. It sounds like it may be coming from the rear end or differential? Because the sound seems to change with wheel speed my instincts lead me to wonder if you may have something simple going on. A brake shoe/pad rubbing? Perhaps the parking brake is sticking or has come apart? Does your truck have rear disk or drum brakes? I'm just throwing some ideas out there. Hope it helps. Edited January 10, 2012 by krmiller07 Link to comment Share on other sites More sharing options...
andreus009 Posted January 10, 2012 Share Posted January 10, 2012 2wd always. Ok. that sounds like it might be a reasonable idea. Is that realistically safe? On my bike, if I pedal the rear wheel, it creates centrigufal force that vibrates everything. That's not even going fast. If I jack it up and get the wheels up to ~40mph, is it going to stay on the jack stands? Might it create insane vibrations and forces because the road isn't there to absorb them? Well, I've done it myself without any issues. Remember, tires are high speed balanced so they shouldn't vibrate too bad unless you get crazy with it. Ideally you have a friend you trust run the gas pedal while you listen and watch. Have him/her bring it up slowly and if things start to make you uncomfortable tell him/her to let off and hit the brake. If things are stable and not shaking like heck then you can walk around the truck listening for your whine. Try different speeds and try listening when you let it coast down. I always had the jack stands under the axle tube, so rested in the dimple/sunk area of the jack stand. Link to comment Share on other sites More sharing options...
stalker Posted January 10, 2012 Share Posted January 10, 2012 deer whistles...mounted on the bumpers Link to comment Share on other sites More sharing options...
5523Pathfinder Posted January 10, 2012 Share Posted January 10, 2012 This is on your pickup right? Extended cab? Im thinking carrier bearing on the rear driveshaft. Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 10, 2012 Author Share Posted January 10, 2012 (edited) This is on your pickup right? Extended cab? Im thinking carrier bearing on the rear driveshaft. yes. my Nissan hardbody. ext. cab. Carrier bearing..that's a good idea. I know I had to take that off when I did my trans swap. I randomly checked it the other day when I was working on my truck. let me make a video of it. maybe it's loose and I didn't notice or maybe someone will notice something I didn't notice. Sorry, I didn't realize that the drive shafts were different on d21s? Edited January 10, 2012 by 1994SEV6 Link to comment Share on other sites More sharing options...
5523Pathfinder Posted January 10, 2012 Share Posted January 10, 2012 All WD21s had a one piece shaft and most hardbodys had two piece. Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 10, 2012 Author Share Posted January 10, 2012 That sounds really plausible. How do I check it? I'm out here under my truck. I took the two bolts off. I took the two bracket things off. It has the tiniest about of play if I shift it front to back. Absolutely zero play up and down or side to side. I can't spin it fast enough with my hand to determine if it's the culprit. Is there maintenance for these bearings? Is it just acting out for some greasy attention? It seems like a $20 part, but it looks like it's kinda part of the drive shaft. Can they be easily replaced? Link to comment Share on other sites More sharing options...
5523Pathfinder Posted January 10, 2012 Share Posted January 10, 2012 Probably the best way is to jack up the back of the truck and support the axle with stands. Make sure the rear tires are not touching the ground. You should have it in 2wd and have someone run the speed up to where you normally hear the noise. Underneath you will need to listen with some kind of listening device. A really long screwdriver works really well(some would use a stethascope). Put one end in your ear(handle is best) and the other on, or near the bearing on some non-moving metal. If the noise is loud, you got a winner. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 11, 2012 Share Posted January 11, 2012 A whistling noise doesn't sound like gears to me, sounds more like an underlubricated shaft or one with a worn bearing. I would look at the carrier bearing, especially if it's been moved from factory for any reason. If the carrier bearing isn't the problem, check the differential to see if anything is metal-on-metal in or connecting to it. I don't know enough about how this transfer case is set up to say if that could be at all a part of the problem. Good luck finding out what's goin' on. Link to comment Share on other sites More sharing options...
1994SEV6 Posted January 11, 2012 Author Share Posted January 11, 2012 Ok, then that can partially rule out the transmission. It sounds like it may be coming from the rear end or differential? Because the sound seems to change with wheel speed my instincts lead me to wonder if you may have something simple going on. A brake shoe/pad rubbing? Perhaps the parking brake is sticking or has come apart? Does your truck have rear disk or drum brakes? I'm just throwing some ideas out there. Hope it helps. hey thanks a lot for the ideas. Luckily, it wasn't anything to do with brakes or anything like that. I wouldn't want to mess with that. It wasn't anything you suggest, but I would have said the exact same thing you did if I wasn't too scared of it being the trans. This is on your pickup right? Extended cab? Im thinking carrier bearing on the rear driveshaft. I think you got it. Thanks a lot. A whistling noise doesn't sound like gears to me, sounds more like an underlubricated shaft or one with a worn bearing. I would look at the carrier bearing, especially if it's been moved from factory for any reason. If the carrier bearing isn't the problem, check the differential to see if anything is metal-on-metal in or connecting to it. I don't know enough about how this transfer case is set up to say if that could be at all a part of the problem. Good luck finding out what's goin' on. It didn't sound like gears to me either. My dad said "hmm..sounds like it might be synchroes winding down" LOL, wut? Just FYI, the M/Ts in these trucks DO make a whistling noise due to being underfilled. I think I noticed you said you had an M/T. Better check that it's overfilled to 5.1l if you haven't already seen that. The noise sounded a little more fierce than actuality on the video. It wasn't anything mean or violent like metal-on-metal in the rear diff would be. To be honest, I thought it might be air being pushed through a small opening. I think it was the carrier bearing. I went outside. Took off the two bolts. Took off the two brackets. Held the driveshaft and spun the bearing 5-10 times. It seemed good. I put it all back together to get it out of the way and finish my t-case project. I took it for a drive and the noise was gone!! I don't even know what happened. Maybe the bolts were under-torqued? I made sure to get them real tight. Link to comment Share on other sites More sharing options...
SchizophrenicMC Posted January 11, 2012 Share Posted January 11, 2012 Might have been. If the bolts are at improper torque, the shaft will sit odd and scrape. Link to comment Share on other sites More sharing options...
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