Transmission Noise - NEED HELP

HI. I bought a used 2005 GT 5 Speed. Very shortly after buying it it began to develop a bad noise. It appears to be coming from the bellhousing. The noise ONLY occurs in one condition. Car in Neutral, Clutch pedal out / released. There is never any noise in any other condition. The noise sounds like a loose bearing, light rythmic knocking. I have pulled the tranny and replaced the throwout bearing with a new one. Little to no improvement. Ideas?

Normal. It is gear clatter. You may also notice it in 4th gear and light load condition. (No load on cluster gear as it is direct drive)
My T5 did it. My brand new magnum xl did it from mile zero.

ATF that is specified is too thin IMO.

You've replaced the obvious culprit so that leaves the pilot bearing. Do you have any difficulty shifting gears?
Your tranny fluid should be Mercon V.

I have the same noise going on, only really manifested after I installed cams. If I lightly rest my foot on the clutch or hold it in then it goes away. Hasn’t really bothered me, doesn’t affect driveability, just kinda annoying to listen to.

Did you replace the clutch master or slave cylinders?

Sounds similiar to dust shield rattle tsb, have you checked that. Theres a few threads on here about it. Here is one.

https://www.s197forum.com/threads/annoying-rattling-upon-start-up.62249/

Aviator said:

HI. I bought a used 2005 GT 5 Speed. Very shortly after buying it it began to develop a bad noise. It appears to be coming from the bellhousing. The noise ONLY occurs in one condition. Car in Neutral, Clutch pedal out / released. There is never any noise in any other condition. The noise sounds like a loose bearing, light rythmic knocking. I have pulled the tranny and replaced the throwout bearing with a new one. Little to no improvement. Ideas?

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Is most likely Tob mine did the same thing finally it started leaking then you will be calling the tow truck.

Sent from my SM-A115A using Tapatalk

Any update from you guys with the rattling trans gears? I have the same issue right now on a 2001 tr3650 behind a 3V with Hot Rod cams. When I'm sitting at a red light at 750rpm idle with the clutch pedal released the damn thing clanks and rattles like a garbage truck. If I press the clutch pedal in while idling the sound completely goes away. The trans shifts great and works fine otherwise, just this annoying and embarrassing noise.

I had the car idling in neutral while up on stands in my garage, I removed the trans inspection plate and watched it idle from underneath, and there is nothing rattling or shaking inside the bell. The clutch fork and spinning pressure plate all looked normal. The noise is certainly internal to the trans.

It only occurs around 750rpm, that's where these cams lope. In neutral and at a higher rpm it makes no noise at all. Obviously it's worsened by the Hot Rod cams shaking the engine and the polyurethane engine and trans mounts translating that shake throughout the car.

This weekend I switched out the Mercon for 3.25 qts. of Synchromesh but that made no difference at all. I'm thinking of replacing about 12 oz. of the Synchromesh with Lucas Transmission Fix based on some other "internet expert" advice. Does that thicker Lucas oil cushion the gears?

Any advice you fellas can share would be appreciated.

No advice short of using non approved, thicker fluid.
My zero mile magnum xl, behind a bone stock 5.0 rattles the same as the T5 did behind the 4.0.

Thanks for the feedback Juice. I don't know what to do with this trans. I wonder if a performance rebuild would solve the issue? Maybe there won't be so much slop in a performance build, like pro-forceperformance.com?

Parker Lewis said:

Thanks for the feedback Juice. I don't know what to do with this trans. I wonder if a performance rebuild would solve the issue? Maybe there won't be so much slop in a performance build, like pro-forceperformance.com?

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I seriously doubt a rebuild would help with that.
I call it "gear clatter" as there is no load on the trans in neutral. Like I said, the T5 did it too.
Raising idle speed may help.
A thicker oil would help, but may damage syncros.
ATF is too thin to cushion gear boxes IMO. Syncromesh fluid isnt much thicker. Gear oil would quiet it for sure. But than cold shifting will be difficult.
So turn up the radio!

Update to Post #8 above, if anyone cares.......
So last night I drained 12 ounces of the Pennzoil Syncromesh from my trans and replaced that with 12 oz. of the Lucas oil trans fix red goopy sauce. I was a bit leery of putting that thick goo into my trans but i can no longer handle the violent clanging sounds of the internal trans gears at idle so I'm willing to try almost anything at this point.

So now my 2001 TR-3650 with MGW shifter is filled with 90 oz. of Pennzoil Syncro and 12 oz. of the Lucas trans fix goop, for a total fluid volume of 3.2 qts. I lowered her off the stands and fired her up and went for a drive. Once everything got up to temp after about 5 miles driving I parked and idled a bit and holy sh*t the sucker was quiet as a church mouse at idle, I was so happy. And there was no difference in the shifts at all, it shifted just fine. My arm was getting tired from patting myself on the back.....then thing changed a bit.

My ultimate success was short lived and things did get a bit more noisy as I drove more, I assume it's because the trans fluid heated up and that thick goo started to thin out a bit, maybe? After around 10-15 miles of diving I circled the Home D parking lot and stopped a few times to idle. I could again hear the trans gears clanking as I described in my post above, but it is not nearly as loud or as consistent as before, but the noise was there and is louder than I'd prefer it to be. I can say the addition of the Lucas goop definitely made a difference, without a doubt. I may try to add more, maybe in 4 oz. intervals to see if it can help keep the noise down at all times. At first I thought this fluid did the trick and solved my issue, but I'm not fully satisfied although it was an improvement.
I'll report back when i add more sauce. I'm debating whether to just add another 4 oz of the Lucas goop or to drain and replace as I did last night so i don't exceed the total fluid volume of 3.2 qts. Hmmmm?

Aviator said:

HI. I bought a used 2005 GT 5 Speed. Very shortly after buying it it began to develop a bad noise. It appears to be coming from the bellhousing. The noise ONLY occurs in one condition. Car in Neutral, Clutch pedal out / released. There is never any noise in any other condition. The noise sounds like a loose bearing, light rythmic knocking. I have pulled the tranny and replaced the throwout bearing with a new one. Little to no improvement. Ideas?

Click to expand...

Input shaft bearing??