Odd chattering in '92 MTX

[Racer X]

I noticed on the way home from RI earlier this month that my SHO was making this odd chattering noise in 3rd and 4th gear, but not in 5th. I dismissed it more or less until today...
...when it became a little louder.

It's not obnoxious, but it's a little unnerving hearing sounds come from my gearbox. I can't really hear it in 1st with the engine noise, but it's there ever so slightly in 2nd, and apparent in 3rd and 4th. 5th I don't hear it at all, but for all I know it could be drowned out by wind noise or hole-in-resonator noise. The noise changes pitch with vehicle speed, not engine speed. Meaning that the pitch will be the same at 50MPH in 3rd gear as it is at 50MPH in 4th gear.

Also, I noticed once that when I downshifted into 2nd gear at around 35 - 40MPH, I could "feel" the chattering in the shift ****.

I don't know what's going on, but I think that a problem with my transmission's final drive set or something wouldn't be completely out of the question.

Please, please... if anyone has some insight as to what I broke and might need to fix, lemme know, aiite?

Good looks.

 

[Bizzy]

The whirring noise may be bearings. Check the level of your tranny fluid first thing. If it's not full then top it off. The bearings are pretty darn tough, I am a witness to exactly how tough they really are.

Chattering is hard to diagnose since there are a few things that could cause it. It could be anything from internal problems to TOB problems. If in doubt you might want to drop the tranny before anything gets worse. The problem with the tranny is that there is nothing that you can really "fix" from the outside with the exception of a few seals and the tranny fluid level.

Edit: I was thinking about this when taking my son to school this morning also....what about your wheel bearings? Those would also make a nice humming/grinding noise which would be consistent at MPH versus RPM. The lower the speed the less likely you would be to hear them also. Just thoughts to think about.

 

[Racer X]

Beth, it's not a wheel bearing issue, I don't think. I've been down that road before, and it doesn't sound or feel like a bad bearing. Some more details:

- You can hear the noise at low speeds also, as long as you're in gear. Once there's no acceleration/ deceleration load on the drivetrain, the noise all but disappears.
- It's becoming increasingly difficult to shift into 1st at a stop, but I'm attributing this to my worn clutch. The 2nd to 1st trick seems to work well to get around that issue.
- The noise isn't there in 5th gear. At all.

*sigh*

 

[Racer X]

OK, now the noise is in 5th gear. It's pitch is still directly proportional to the vehicle speed, however, it gets wicked loud when I clutch in? That almost always means a worn TOB, but a worn TOB almost always changes pitch with engine speed, and not vehicle speed. Any more ideas, Beth? I'm all idea'd out.

 

[93SHO'nOFF]

The trans may have may have a tooth broken off a gear or a Input Shaft bearing going bad inside.If you drain the fluid and the color of the oil has a metallic tint or chunks of metal coming out,you will know it's a internal trans problem and not a TOB or clutch concern.
Later,
Mike

 

[Bizzy]

I'm thinking TOB with the difficulties you're having shifting. Don't force it into gear though, you can damage the synchros that way. Have you dropped the tranny yet or drained the fluid?

 

[Racer X]

Welp...

I installed a drainplug when I did the clutch recently. Besides the 3 quarts of GEAR OIL that drained out, there was nothing else out of the ordinary inside.

3 quarts of ATF later, it's much quieter, but still the noise is there to a lesser extent. And now to add to it all...
I've got a high pitched whirring that changes pitch in relation to engine speed. Anything over 4500RPM, and it sounds like I have a small turbo spooling under the hood! Which, as cool as it sounds, is probably indicative of a problem somewhere in there.

I'm starting to go

 

[Racer X]

Death knell?

http://www.supermotors.org/getfile/170728//4th gear.mp3

Right click, save as.

That's the noise, as of recent. Obviously, this tranny is toast, but until I can install a new (aka working) one, how long do you think it can go on like this? And what is everyone's thoughts on rebuildability? Would this be a good first rebuild attempt for me, or should I scrap that idea?

In addition to what I posted above, I can now hear the synchro's working in 1st - 4th gears, and it'll pop out of 1st (with a dramatic slam noise sometimes, I might add. ), unless I shift into first while still in motion (5MPH is enough). And 5th feels like it isn't always in the same place.

The linkage is definitely getting inspected, but I doubt that's the culpirt. When I check it, are there any specific wear areas I should look at?

 

[Racer X]

The linkage is definitely getting inspected, but I doubt that's the culpirt. When I check it, are there any specific wear areas I should look at?

Bump.

Tranny is coming out this weekend folks, and I wanna get this right the first... er... second time around. Any thing specifically I should look at with the linkage, as far as wear areas?