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I have a hum from the drivetrain somewhere. It stops under acceleration and does not increase when the car is thrown side to side. What could this be? Wheel bearings always seems to be the answer, is this a tough job? I'm not much of a mechanic. The car runs great and was very well taken care of before i got it.
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Wheel Bearings
- Thread starter spooch22
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guzzul
Jedi Warrior
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What Triumph do you have? TR? Spit?
Doesn't sound to me like a wheel bearing, I'm not sure why they would quiet down on acceleration. Sounds more like something that is affected by the torque of acceleration, like gearbox, u-joints or differential.
Is the 'hum' loud? Is it more like a higher pitched whine, or a low-pitch hum? Does it distinctly disappear when you accelerate? Does it sound like its coming from the front of the car, middle, or rear end? Does it sound like it is in synch with road-wheel rotation or engine rpm? Does it change pitch when you shift gears up or down? Or stay the same (like a steady road-speed noise)?
Doesn't sound to me like a wheel bearing, I'm not sure why they would quiet down on acceleration. Sounds more like something that is affected by the torque of acceleration, like gearbox, u-joints or differential.
Is the 'hum' loud? Is it more like a higher pitched whine, or a low-pitch hum? Does it distinctly disappear when you accelerate? Does it sound like its coming from the front of the car, middle, or rear end? Does it sound like it is in synch with road-wheel rotation or engine rpm? Does it change pitch when you shift gears up or down? Or stay the same (like a steady road-speed noise)?
TheAssociate
Jedi Hopeful
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I agree, guzzul.
I don't think it would be a wheel bearing. A bad wheel bearing sound will always change when going around a sharp corner etc.
Without hearing it myself, sounds like you've got a bad bearing in the driveline. Output shaft, universal joints, bearing in the differential.
Adam H.
____________________________________________________________
1972 Triumph Spitfire.
I don't think it would be a wheel bearing. A bad wheel bearing sound will always change when going around a sharp corner etc.
Without hearing it myself, sounds like you've got a bad bearing in the driveline. Output shaft, universal joints, bearing in the differential.
Adam H.
____________________________________________________________
1972 Triumph Spitfire.
guzzul
Jedi Warrior
Offline
Got me stumped. I must say, I am not familiar with TR6 axles, and they are different from Spitfires, so you could have a problem there that I wouldn't know about. Some of the more knowledgeable forum members could maybe help out.
Having said that, its wierd that this noise disappears under acceleration. Wheel bearings generally don't change on acceleration, and as Adam H. says, they will usually get louder on one side or the other on cornering.
Similarly, differential crown/pinion noises usually get louder on acceleration, not quieter. Bearing noise in the diff shouldn't change on acceleration, but it's possible I guess. Have you noticed any oil leaking from around the differential shafts or the pinion seal?
When u-joints wear, they tend to 'knock', not 'hum'. Prop shafts don't usually hum either, they typically vibrate and shake if they're out of balance. And it should get worse as you go faster.
Have you checked simple stuff? Tire treads ok, tire inflation, wheel nuts, etc?
You might also check the differential rubber mounts. Could be you are getting vibration transmitted into the car because they are worn and a little loose, and the torque of acceleration compresses them again. Usually you will get a 'thump' on startup if the rubber mounts are getting worn, though, as the diff twists on startup.
Sorry, that's all I can think of. Hopefully another member will have more experience to share. It will be interesting to see what this turns out to be.
Having said that, its wierd that this noise disappears under acceleration. Wheel bearings generally don't change on acceleration, and as Adam H. says, they will usually get louder on one side or the other on cornering.
Similarly, differential crown/pinion noises usually get louder on acceleration, not quieter. Bearing noise in the diff shouldn't change on acceleration, but it's possible I guess. Have you noticed any oil leaking from around the differential shafts or the pinion seal?
When u-joints wear, they tend to 'knock', not 'hum'. Prop shafts don't usually hum either, they typically vibrate and shake if they're out of balance. And it should get worse as you go faster.
Have you checked simple stuff? Tire treads ok, tire inflation, wheel nuts, etc?
You might also check the differential rubber mounts. Could be you are getting vibration transmitted into the car because they are worn and a little loose, and the torque of acceleration compresses them again. Usually you will get a 'thump' on startup if the rubber mounts are getting worn, though, as the diff twists on startup.
Sorry, that's all I can think of. Hopefully another member will have more experience to share. It will be interesting to see what this turns out to be.
Back in the dark ages, when faced with worn & noisy diffs, we would simply add 40 or 50 % STP to the hyphoid lube. Crude you say? darn right and worked super!!Never had a failure of a diff we did that way.Big savings over a set of new bearings and the set-up of a diff.
MD(mad dog)
MD(mad dog)