Transmission output bearing noise?
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Junior Member
Joined: Aug 2016
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From: Western NY
Transmission output bearing noise?
Hi all, forum newb, but been wrenching since the 70's.. Looked for something on this, but didn't find anything.
My wife's car is an 07 3i manual with ~116k miles (we bought it with about 40k miles and have had it about 5 years), and there's a noise that fooled me into thinking it was a wheel bearing, but it's not. I found this out, when I put the car on a lift to replace said bearing last night.
The sound is the typical bearing rumble (100% varies with car speed, and changes slightly as you veer right or left at speed), and really noticeable inside the car. Not so much outside, you have to be in the right spot to hear it outside.
If you lift one front wheel at a time off the ground, and let the car idle in 5th gear (with both wheels off the ground it idles about 20 mph, with 1 wheel off the ground, it spins about 40 mph), it will make noise with one wheel lifted (driver side) but not the other (passenger side). This is what made me think it was a bearing.
When I put the car up on a lift last night, I checked the bearings and they seemed fine, so I grabbed a stethoscope to listen to the entire drive-train with the wheels spinning, idling in 5th gear. The sound was clearly audible inside the car, but hard to find from underneath. With the scope, both wheel bearings were quiet, the passenger side transfer bearing was quiet except for a click that could be heard every now and then, the engine block was quiet, the main tranny housing was quiet. The only sound I heard resembling the rumble inside the car, was touching the output housing on the tranny, and it was not loud. (I'm guessing the tranny mount is transferring the vibration to the firewall where it is resonating)
I even rotated the tires, to verify that it wasn't tire imbalance that was making the noise.
Are the output bearings replaceable without removing and rebuilding the tranny?
Any other thoughts?
My wife's car is an 07 3i manual with ~116k miles (we bought it with about 40k miles and have had it about 5 years), and there's a noise that fooled me into thinking it was a wheel bearing, but it's not. I found this out, when I put the car on a lift to replace said bearing last night.
The sound is the typical bearing rumble (100% varies with car speed, and changes slightly as you veer right or left at speed), and really noticeable inside the car. Not so much outside, you have to be in the right spot to hear it outside.
If you lift one front wheel at a time off the ground, and let the car idle in 5th gear (with both wheels off the ground it idles about 20 mph, with 1 wheel off the ground, it spins about 40 mph), it will make noise with one wheel lifted (driver side) but not the other (passenger side). This is what made me think it was a bearing.
When I put the car up on a lift last night, I checked the bearings and they seemed fine, so I grabbed a stethoscope to listen to the entire drive-train with the wheels spinning, idling in 5th gear. The sound was clearly audible inside the car, but hard to find from underneath. With the scope, both wheel bearings were quiet, the passenger side transfer bearing was quiet except for a click that could be heard every now and then, the engine block was quiet, the main tranny housing was quiet. The only sound I heard resembling the rumble inside the car, was touching the output housing on the tranny, and it was not loud. (I'm guessing the tranny mount is transferring the vibration to the firewall where it is resonating)
I even rotated the tires, to verify that it wasn't tire imbalance that was making the noise.
Are the output bearings replaceable without removing and rebuilding the tranny?
Any other thoughts?
Thread Starter
|
Junior Member
Joined: Aug 2016
Posts: 2
Likes: 0
From: Western NY
About 155k miles on it now and still driving daily, and still no noise.
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