Help Identifying Transmission Noise

[MurphinDC]

After a spirited drive yesterday as I was coming into my housing development I noticed a sound coming from the engine/transmission when I released the clutch.  The throw-out bearing has been making some noise and I'm thinking what I'm hearing is it.  Anyway, before I start down the troubleshooting path...fluid, guibo, brackets, shifting platform and bushings, I thought I would run the sound by the experts.  Let me know your thoughts. The car has a Getrag 245 5 speed and standard rear end.  See attached video

 

Thanks for the help!

Murph

 

[jimk]

If you mean by "releasing the clutch" taking your foot off the pedal, then the noise happens when the transmission turns.  Sound sounds like serious trans trouble it I got the foot in the right place.

[MurphinDC]

Yes, you are correct....when I take my foot off the pedal and the transmission engages/turns.

[andyleonard]

With the car at rest and the box in neutral, clutch pedal out, the only things spinning in there are the input shaft and the layshaft. So you're hearing  - probably - one of those bearings protesting.

If this gearbox is rebuilt or new to you and this is the first time you've gotten the box really hot, you can drop the oil, look for chunks, and try a heavier oil. 

If this is a seasoned box you know well and it never did this before under similar circumstances, drain the oil, look for bearing chunks, and get on the internet and start hunting a bearing set.

[MurphinDC]

Let me add some clarity.  The sound appears with the clutch pedal out, not depressed and IN GEAR.  The sound you hear was when the car was in reverse.  It appears all the time when in reverse and off and on when in first or second. 

 

I will begin analysis hopefully tomorrow by first draining the fluid.  

[tech71]

11 hours ago, MurphinDC said:

The car has a Getrag 245 5 speed

Uh oh.....

 

9 hours ago, andyleonard said:

get on the internet and start hunting a bearing set.

If only it was that easy

Edited November 25, 2022 by tech71

[andyleonard]

I didn't say *finding*, I said *hunting*. Lack of parts is a big piece of a repair decision.

[TobyB]

Oy, that does sound unhappy.

 

Rule out the CSB first, and the guibo second.

 

Does it change when you're loaded vs. on the overrun?

 

t

 

[tech71]

13 hours ago, andyleonard said:

I didn't say *finding*, I said *hunting*. Lack of parts is a big piece of a repair decision.

Hunt all you wish, most parts for Getrag 245s including critical bearings are unobtainable. My search took me all the way to Russia (before the trouble) and absolutely no joy.

No countershaft bearings, no layshaft cage bearings, no gear sets, no shafts... nothing

Edited November 25, 2022 by tech71

[MurphinDC]

45 minutes ago, TobyB said:

Oy, that does sound unhappy.

 

Rule out the CSB first, and the guibo second.

 

Does it change when you're loaded vs. on the overrun?

 

t

 

Thanks.  Sorry somewhat a novice....loaded vs on the overrun?  My plan is to get it on stands tomorrow and start first with fluid and will check the guibo.  How do I troubleshoot the CSB?

[TobyB]

Loaded is when you're accelerating, overrun is coasting with the engine slowing you down.

 

If the transmission or the diff's coming apart, that noise changes a lot.  If the center support is a mess,

usually it's constant- ish.  If you don't see anything obviously wrong with guibo, center support or driveshaft,

look carefully for something touching either the body (often the top of the tunnel) or the exhaust, or the exhaust

hitting something.  You can sometimes feel it, too.

Taking the driveshaft off is sometimes the only way to really make sure it's OK, as the center bearing

can get pretty noisy before it tears itself free.

 

If you can get it safely supported on 4 stands, I've carefully crawled under the car with it running and in gear

to try to diagnose driveshaft problems- I'm not saying it's SAFE, just that I've survived it without scars!

 

That noise does sound like bearings, tho, sadly.  But sounds over the internet are notoriously hard to diagnose.

 

t

 

[2002iii]

On 11/24/2022 at 12:51 PM, MurphinDC said:

Let me add some clarity.  The sound appears with the clutch pedal out, not depressed and IN GEAR.  The sound you hear was when the car was in reverse.  It appears all the time when in reverse and off and on when in first or second. 

 

I will begin analysis hopefully tomorrow by first draining the fluid.  

From this description and the sound I would suspect the input bearing is failing.

[MurphinDC]

Got under the car with the engine running and put it in reverse, which is when I hear the noise the most.  The sound appears to be coming from the transmission and near the front.  The guibo, driveshaft and center support bearing are only a couple of years old as the PO installed them when he pulled out the LDS before he sold it to me. The sound did not appear to be coming from those parts.  I also drained the fluid and only found very very small bits of metal, no chunks or anything of significance (see picture).  That's two drops of fluid on he bottom of the filter.

 

Guess I'll start making calls to see about getting it rebuilt.  I know Metric Mechanic is one choice and I see Korman also does them.  I'm on the East coast so any other suggestions would be appreciated.

 

Any other thoughts or suggestions?

Edited November 27, 2022 by MurphinDC

[Dudeland]

On 11/24/2022 at 2:15 PM, andyleonard said:

With the car at rest and the box in neutral, clutch pedal out, the only things spinning in there are the input shaft and the layshaft. So you're hearing  - probably - one of those bearings protesting.

If this gearbox is rebuilt or new to you and this is the first time you've gotten the box really hot, you can drop the oil, look for chunks, and try a heavier oil. 

If this is a seasoned box you know well and it never did this before under similar circumstances, drain the oil, look for bearing chunks, and get on the internet and start hunting a bearing set.

There are no bearing sets and layshaft bearings are NLA. Input shaft bearings are available. You are in trouble. 

 

 

[tech71]

I recall that the guy at MM can open up and determine whether you have a rebuildable core in just a few minutes. Not sure what he’s looking at, possibly the actual counter shaft gears… 

Anywho, what ever it is, if it’s bad not even they can repair.

Be very careful who you choose to repair. Very few shops will be competent/ experienced/equipped to handle it.   Sorry

 

Edited November 28, 2022 by tech71