Noisy transmission bearings vs noisy diff: how to tell

If it is transmission noise it will be noisy when the car is standing still, will likley change depending on what gear you are in. The sound emitted from worn bearings is in my experience is more of a rumble and worn gears tend to howl.

Tegger, the only time I have had a similar problem was when the differential bearings went out on an automatic transmission car of mine. It started howling at highway speed, and was somewhat less as the car decelerated. It, in this case, did not quiet as you got off the accelerator, it just changed with crankshaft rpm.

I know this doesnt help much. I guess you could jack it up, put it in gear, and listen for the source of the noise.

"*" wrote in news:01c8342b$3436bde0$a693c3d8@race:

I'm not sure I understand these sentences. With the clutch engaged (pedal released) in neutral, the input shaft is spinning everythng inside the gearbox, no?

My usual mechanic (now 50 miles away) tests for noisy bearings by parking the car near a wall so he can hear better, then repeatedly pressing and releasing the clutch in neutral.

Last time he checked, which was two years ago, he said the bearings would rattle under that test when the pedal was released.

I asked him when I would know it was time to replace the tranny, and he said when it "sounds like a freight train".

I had two Toyota T50 trannies develop bad 5th gear bearings. They sounded just like this (whining/howling), but only when I was actually in 5th. The noise I've got now happens no matter the gear, only at 45-50mph, and only once the tranny warms up.

The car is a '91 Integra with almost 300K miles on it.

"HLS" wrote in news:UZ24j.74674$ snipped-for-privacy@newssvr29.news.prodigy.net:

This is iteresting. I wonder if mine will get like this with time. Right now it gets totally quiet when you're off the gas in gear.

Diff bearings sound right to me. Final drive speed changes linearly with car speed.

With the weather we've got right now, I'm not doing any servicing for a long while. No garage, you see.

z wrote in news: snipped-for-privacy@p69g2000hsa.googlegroups.com:

It's not possible for me to do any listening that would tell me anything. Let's just say my hearing is "approximate".

I'm just going to let it go until it's too loud to tolerate, then replace the tranny.

Thanks.

"*" wrote in news:01c83bfc$cea24ec0$5893c3d8@race:

I know the gears (except for Reverse) are actually in constant mesh, and that what locks them to the output shaft are the dog teeth on the synchro assemblies.

Thinking more carefully, the INPUT shaft and all the GEARS would be spinning in neutral (clutch engaged), but the OUTPUT shaft would not, since none of the output shaft gears would be locked to the output shaft.

That being the case, the output shaft bearings would not be spinning when the car is not moving, so there would be no way to check for noise from them with the method my mechanic used last time he did his quick check. All the other bearings could be checked by my mechanic's quickie method, however.

I see why, now. Thanks.

Depends on the trans. Some trans have a synchro engagement of reverse so the gears are in motion along with the others. I would check that the oil is of the correct type and weight for the trans.

"Chas Hurst" wrote in news:N-KdnSC0D7scZcLanZ2dnUVZ snipped-for-privacy@comcast.com:

In this particular tranny reverse gear slides.

And the oil in question is Honda genuine MTF and has been changed every year since new in 1991.