Guess the gearbox noise (video)

[KCL]

Hi all, I just put the gearbox back in after replacing worn parts with new from TRGB:

• Clutch
• Clutch Cover
• Throw out bearing
• Bearing carrier (with a bronze one - with anti-rotation pin)
• Front extension + gasket + seal (the shaft the bearing carrier slides on)
• Cross shaft, bushings, fork, tapered pin

So pretty much all the items that experience wear, and boy, were they worn(!)

I lightly greased the front extension & carrier with lithium grease, the splines that engage with the clutch were lightly greased with the grease that came with the clutch kit

After torquing all the bolts down I notice the following (??bearing??) noise when the clutch is engaged (i.e. the clutch pedal is NOT pressed).

It's entirely possible I've messed something up or misaligned something but I don't think I did.

I'm trying to diagnose what the sound is (GB is in neutral), so far my guesses are either:

1. Noisy throw out bearing <-- but it's new
2. The throw out bearing almost touching and rubbing against the fingers
3. ⁠⁠Gearbox input shaft bearing

My plan tomorrow to check if it's the input shaft bearing is to get the rear wheels off the ground, put the box in 4th gear (1:1) and slowly release the clutch listening if the noise modulates with wheel speed.

Perhaps someone who's been here before would know.

Edited July 7 by KCL

[Z320]

Hi,

if you press the clutch the noise is gone --> it is not the release bearing.

In my opionion it is the main bearing of the ingoing gb shaft (no worry) or the laydown shaft.

They spins (noisy) when the clutch is NOT pressed, and do not spin when the clutch is pressed.

Very likely the gb made that noise already before your repair,

but you did not notice it with the tunnel installed.

Ciao, Marco

Edited July 7 by Z320

[KCL]

16 minutes ago, Z320 said:

Hi,

if you press the clutch the noise is gone --> it is not the release bearing.

In my opionion it is the main bearing of the ingoing gb shaft (no worry) or the laydown shaft.

They spins (noisy) when the clutch is NOT pressed, and do not spin when the clutch is pressed.

Very likely the gb made that noise already before your repair,

but you did not notice it with the tunnel installed.

Ciao, Marco

Oh yes, good thinking about the layshaft too, that will be spinning when in neutral too, thanks.

Yes, it likely was noisy before I repaired and I just didn't notice with all the other rattly loose components. I don't necessarily want to 'fix' this sound, I just like to understand the mechanics of the car better and know what sounds are being caused by what.

[BlueTR3A-5EKT]

sounds like many others I have heard.   No tunnel allows the noise to be noticed.  

I trust you have got sufficient, of the right type of oil in the gearbox and overdrive assembly?   Easy to do the oil with the tunnel out.

Plus you put the two dowel bolts through the gearbox case and engine backplate first. They do the gearbox alignment      (The 3/8” diameter ones) all others except starter motor are 5/16” bolts or nuts  

 With  the tunnel out you can also confirm the overdrive works and the reverse gear switch for the reversing lamps functions.

[Malbaby]

Probably not the problem, but you did not mention the state of the pilot bearing.

[KCL]

21 hours ago, BlueTR3A-5EKT said:

sounds like many others I have heard.   No tunnel allows the noise to be noticed.  

I trust you have got sufficient, of the right type of oil in the gearbox and overdrive assembly?   Easy to do the oil with the tunnel out.

Plus you put the two dowel bolts through the gearbox case and engine backplate first. They do the gearbox alignment      (The 3/8” diameter ones) all others except starter motor are 5/16” bolts or nuts  

 With  the tunnel out you can also confirm the overdrive works and the reverse gear switch for the reversing lamps functions.

I use Penrite GB40 filled 5 minutes beforehand and fitted dowel pins in the correct location. The O/D works just fine.

21 hours ago, Malbaby said:

Probably not the problem, but you did not mention the state of the pilot bearing.

The pilot bearing looked and felt ok.

 

I jacked the wheels off the ground and tested in neutral, 1st, 4th, and reverse.

The sounds modulate with speed, and disappear with the clutch disengaged so probably it’s just normal gearbox noise I hadn’t noticed before, mainly the input shaft bearing.

Perhaps it’ll go away with new bearings when I overhaul the gearbox this winter.

But for now I’m satisfied it’s not anything I’ve caused by replacing the clutch or any of the other parts or by enthusiastically wrestling with the gearbox.

Edited July 8 by KCL

[Waldi]

I fitted my GB last week and did the same you did. Without the tunnel I heard noises that I never heard with the tunnel installed.

After fitting the tunnel and carpets, the sound was like it should be.

Waldi

[Hamish]

10 hours ago, KCL said:

I use Penrite GB40 filled 5 minutes beforehand and fitted dowel pins in the correct location. The O/D works just fine

 

you’ll need to check the gearbox oil again it can take quite a time to settle even more so with an overdrive it needs 15-20 mins for it to find the final levels so you may need to top up a couple of times.