Six speed box - How Noisy?

[MATTYBOY]

I have just bought a 97 supersport with the six speed box. The box is great to use and the changes are all good with strong syncro but when the car is ticking over and the clutch is not depressed the box is very rattly, and I would like to know if this is usual or if there is a problem.

Any info greatly appreciated


Matt

[Risky]

That's normal

[Gaspowered]

Pictures?

[Seven Smiles]

Anyway...

Introduction to Caterham abbreviations :

TADTS They All Do That Sir

[subirg]

Yep, normal. Mine has always done it since new. I asked the factory about it and they told me it's normal. Doesn't hurt anything.

[nomisesor]

Allied question re 6spd SS box - is it TADT to have a particularly penetrating whine in 4th (but not other gears) at ~40mph? Though it seems to be coming from further back (differential), that seems unlikely as presumably it wouldn't be gear dependent.

[grenpayne]

Yes, mine whines in 4th more than any other gear as well and also seems to be coming from the LSD. No idea why! I don't mind it though as I only notice it when I'm in a 30 limit in 4th.

[DCL]

I think gearbox and drive chain noises can come from the diff area. The gearbox (under dive) is solidly connected to diff and it seems to be the area where the minimal bushing transmits noise most.

[MATTYBOY]

Thanks for the info, has set my mind to rest.

Piccy of my P & J




Matt

[ForzaGilles]

grenpayne said:

Yes, mine whines in 4th more than any other gear as well and also seems to be coming from the LSD. No idea why! I don't mind it though as I only notice it when I'm in a 30 limit in 4th.

My Superlight is exactly the same.

[Matt UK]

Risky said:

That's normal

+1

[SLR400]

If the rattling disappears when you depress the clutch then it's most likely to be the clutch release bearing, not the gearbox, particularly if the gearbox operates up and down sweetly. If it is the CRB then TADTS.....

[Red Seven]

SLR400 said:

If the rattling disappears when you depress the clutch then it's most likely to be the clutch release bearing, not the gearbox, particularly if the gearbox operates up and down sweetly. If it is the CRB then TADTS.....

No. The gearbox rattles when it's in neutral, and the clutch is engaged because the input shaft and layshaft of the gearbox are connected to the engine. If the tickover is not smooth (which a supersport with a light flywheel won't be), then the gearbox rattles. The rattle dissapears when the clutch is depressed because the rotating engine is no longer connected to the gearbox.
Wilder cams, set with more overlap, a plenum, and a light flywheel, leads to a lumpy tickover that exagerates the noise from the gearbox.

A knackered CRB is more likely to make a noise when the clutch is depressed (and the noise can often be felt through the clutch pedal).

PS - my 6 speed also whines more in 4th gear than any other gear.

[jagseven]

My 4th gear also whines terribly - been like that since new when I swapped out a 5 speed. It sounds like the diff but it's not.

[Supra Chewie]

I wouldn't worry too much. People expect too much from Caterhams. You're only sitting a few feet from the Ford Sierra diff and inches from the gearbox and unlike the donor car there's no sound proofing and extra mass to absorb the noise and vibration.

[BertBert]

jagseven said:

My 4th gear also whines terribly - been like that since new when I swapped out a 5 speed. It sounds like the diff but it's not.

Yup it's sposed to do that

[rubystone]

CRB is usually the cause of the noise. If it whines after you put your foot on the clutch, you could have a bearing problem; I've had two 'boxes rebuilt for that reason on two different cars. Aside from that, the 'box and 'diff really shouldn't be noisy (my CRB is massively noisy BTW - I just ignore it....)