Transmission noise – Differential problem?

[everthine]

Here’s the problem I’m having: an increasingly worsening grinding/rumbling speed-related noise coming from the transmission; more specifically the differential area (I think). When I bought the car (6 mo ago) the sound was faint and only heard at 50mph+, and I thought it was a wheel bearing. Replaced those and it wasn’t. After reading this forum I thought it might be the CV’s. I’ve replaced those now, too.

Grumbly noise is still there, and there’s enough to a transmission that I don’t know what could be making it. Is there a differential bearing that fails like this?

More info:
-1993 V4.
-When I bought the car I replaced the clutch, too. Refilled transmission fluid, etc.
-Low speeds the sound is rhythmic but not quiet, high speeds it is a loud rumble and I have started to notice the vibration through the pedals.
-Car can be in neutral or any gear. Running or off.
-I sense a slight difference when turning, but not much difference. Can’t remember, but this difference may only be there when turning hard lefts at freeway speeds.

Any thoughts or suggestions? Thanks in advance.

[hgallegos915]

wow v4? jk I just had too

if its grinding,, its bad... checkt he axles tho you never know maybe its just a bearing or a shaft rubbing on something.

If its just noise, I would let it be, mine has transaxle noise but its been good.. sounds like a motorcycles transmission sometimes.

[Newfie_dan]

Drain the trans see if there is any heavy metallic dust or chunks in it, differential noise would be more pronounced when turning left or right when there is actually differential action taking place, also check the fluid level once its been refilled a few times after driving see if you are possibly leaking any. Use something that is cheap and good like gm syncromesh or redline mtl, the trans does not take much so its a cheap means of checking the condition of the trans. If all looks good it could be just bearings and in your case it sounds more like a bearing related issue. How is the alignment and tire condition of the mx3?

[everthine]

I drained the transmission twice: once for the clutch, and once to install the CV halfshaft's. I looked and didn’t notice any sizable metal chunks/flakes. It also didn’t appear unreasonably low between the 2 jobs, nor is there any sign of leaking.

The alignment is fine with no unusual tire wear. hgallegos915, you mention checking the axles, I replaced the halfshafts, is that the same thing, or what am I looking for when I check them? Is it possible that whatever is driving the axle is bent, rather than the axle itself?

I agree with you both, that it does sound like a bad bearing noise. I’m hesitant to ignore it because it certainly is getting worse with time; also it is becoming loud and annoying. So, if it is a bearing problem, what next? Complete transmission disassembly and look for one that is bad? Can a differential bearing be replaced without removing the transmission and all the guts?

Thanks again.

[Newfie_dan]

wheel bearing would have some play in and out on the wheel side, front to back is tie rod ends, the axles he mentioned are indeed the halfshafts, to check the halfshafts you look for up and down movement on the halfshaft while forcing up and down on it also try in and outward, they should be nice and stiff, a little play is not to bad but if you hear a click then they are getting worn out. A worn trans bearing would not necessarily make you feel vibration through the pedals unless that bearing is severely worn out.

[everthine]

Something is severely wearing out. I just can't find it yet...

[clarkandrew45]

I drained the transmission twice: once for the clutch, and once to install the CV halfshaft's. I looked and didn’t notice any sizable metal chunks/flakes. It also didn’t appear unreasonably low between the 2 jobs, nor is there any sign of leaking.

The alignment is fine with no unusual tire wear. hgallegos915, you mention checking the axle assembly, I replaced the halfshafts, is that the same thing, or what am I looking for when I check them? Is it possible that whatever is driving the axle is bent, rather than the axle itself?

I agree with you both, that it does sound like a bad bearing noise. I’m hesitant to ignore it because it certainly is getting worse with time; also it is becoming loud and annoying. So, if it is a bearing problem, what next? Complete transmission disassembly and look for one that is bad? Can a differential bearing be replaced without removing the transmission and all the guts?

Thanks again.

Have you check the axle assembly before replacing it? My friend has the same problem, but the mechanic advice her to simply check the axle and if this is not bent, there is no need to replace that.