1998 Pontiac Sunfire NOISE COMING FROM TRANSAXLE

Tiny
COURT_MAC4
  • MEMBER
  • 1998 PONTIAC SUNFIRE
  • 2.2L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 230,000 MILES
I have the exact problem mentioned by another Sunfire owner. I'll copy and paste here:

I got a 1998 Pontiac Sunfire and got a loud grinding noise what appears to be coming from the transaxle on the passenger side of the vehicle. This noise is real evident as you are loading up the transmission and shifting through the 4 speed automatic transmission. It will smooth out once you get up to cruising speed. I've changed out the right side CV shaft assembly, the right hub assembly and replaced the bearing on the strut mount over on the right side. I'm at the end of the road with this issue. I sure could use some help. Also, the noise is even more evident when you have a passenger over in the right side seat. Sounds crazy doesn't it?

Can you replace the part where the axle fits into the transmission (transaxle I guess). I already replaced the hub assembly and the axle. "HELP!", . Thanks.
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Friday, October 10th, 2014 AT 6:44 PM

4 Replies

Tiny
CARADIODOC
  • EXPERT
The problem is you can't go by where the noise sounds like it's coming from. On older Chrysler products with inexpensive pressed-in bearings, it was real easy to tell which side was bad by driving the car. You can't do that with bolted-on bearing assemblies.

There's two ways to find the noisy bearing. One is to raise the front wheels off the ground, reach over the top and wrap your fingertips around the coil spring, then feel for the vibration when you rotate the wheel. My preferred method is to run the car in gear on a hoist, then listen next to each bearing with a stethoscope. One will sound a bit rumbly, but then the noisy one will be obviously much louder.

The advantage with bolted-on bearing assemblies is if you replace the wrong one, you can put the old one on the other side.

Also be aware a lot of new bearings are damaged by improper installation procedures. There must never be any vehicle weight on it unless the axle nut is torqued to specs. That value is pretty high on GM vehicles and must be set with a click-type torque wrench. A lot of people set the vehicle on the ground so the wheel won't turn and they can tighten the nut. At that point the bearing has been damaged and will be noisy. Instead it's real easy to stick a screwdriver in a slot of the brake rotor so it can't turn, then tighten the nut.
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Friday, October 10th, 2014 AT 9:45 PM
Tiny
COURT_MAC4
  • MEMBER
A pile of great info. I did have the front end jacked up, and the noise is coming from the transmission side of the right axle, but it could be the the CV joint on the new (scrap yard) axle. I'm hoping that is the problem. If not, and it is where the axle enters the transmission, can you tell me the name of the parts involved. Thank you very much for very helpful information, it's very much appreciated.. Courtney.
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Friday, October 10th, 2014 AT 11:01 PM
Tiny
CARADIODOC
  • EXPERT
Inside the transmission housing is a bushing the axle shaft rides on. Failure of those is very rare, and if that bushing gets chewed up enough, the inner cv joint can move off-center enough to move away from the seal and you'll have leaking transmission fluid. There's also a bearing right inside of that bushing that the differential assembly rides on. I've heard those make noise while standing under the running vehicle, but I've never heard that noise inside. You have to remember that those parts don't rotate very fast. They rotate at the same speed as that wheel.

For that same reason the cv joints on that axle shaft rarely make noise either. The outer one can cause a clicking noise that's worse when you're turning and when it's under load, but for an inner joint to make noise, it would have to be so terribly worn that it would cause a pile of other symptoms first. Basically what they will cause is a wobble in the steering wheel during acceleration at lower speeds.
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Friday, October 10th, 2014 AT 11:59 PM
Tiny
COURT_MAC4
  • MEMBER
Well, thank you for all that info. I, m sure it's coming from those bushings or bearings where the shaft enters the transmission. There is no fluid leaking from the seal, but the axle wobbles quite a bit. Totally lost as to what is causing such a loud scraping, rumbling noise is. It vibrates all the loose plastic in the car. Might just have to see it for parts. Thanks again, you've been very informative. Take care.
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Saturday, October 11th, 2014 AT 9:49 AM

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