Gearbox whine @ low revs

[DrewBear11]

Hiya guys,

This has been going on for a while now so i thought id better have a look into it.

When driving along im getting a quieting whining noise from the passenger side of the car, when the revs are between say 1800-2000RPM in 3rd, 4th and 5th. Its only when the car is decelerating with no throttle output. Once I push the throttle the sound stops.... Kinda hard to explain if you can understand what I mean. Also the sound stops when I push in the clutch ?

Just wondering if its definitely clutch/gearbox related or if it could be anything else resonating or rubbing somewhere ? I've got a polybush'd dogbone mount...

It has been making this exact noise for a long time now... months i'd say... Just wondering if there's anything else i should be checking out ?

Any advice is much appreciated

Thanks

 

[MullyBaby]

Did you ever find out what this was?

Mine has the same symptoms, had the box just rebuilt by Agency Transmissions but still there? New driveshaft did'nt fix it either....

 

[Silent_Scone]

input shaft bearing. Get a video up tbh

 

[MullyBaby]

A video wouldn't pick it up to be honest, its a distant/ quiet whine, Agency said they replaced the input shaft bearing, spoke to them and they don't know what it is either, but they did say if it gets worse/ goes bang then they will fix it for free.

Would a wheel bearing be affected by throttle load? (not really noiser on cornering though?)

 

[Silent_Scone]

Possibly if it's bad enough / enough play when they get hot. But there'll be play in the wheel. If it's driving ok just ignore it...I had similar when my diff bearing was making a racket but it went on for ages like it.

They're great cars but they're also about as well built as an impact parachute. Drown it out with the radio

 

[MullyBaby]

Drown it out with the radio

This FTW

 

[MullyBaby]

Just a quick thought, this only became noticable when I did a clutch change, new Valeo clutch and bearing, but I also replaced the clutch cable with the newer style one with weights on it, might have a look to see if the weights are making the clutch fork resonate the the thrust bearing?

#clutchingatstraws

 

[johnnyd]

Mine has done this for a long time. All gears roughly between 1500-4000rpm when off the throttle. As soon as i press the clutch the noise goes. Apart from being annoying and making my car sound rubbish there doesn't seem to be any other symptoms of this so i have just learnt to ignore it. It is loud though.

My car is completely standard btw. The engine, gearbox and clutch have not been touched apart from servicing.

 

[182_Adam]

could possibly be your final drive on the end/bottom of your gearbox...that tends to happen when things aren't done up tight enough.

if it's happening on both throttle and off and you're sure its coming from gearbox, could well be the bearings (possibly not fitted correctly or faulty) or lack of gearbox oil.

 

[MullyBaby]

I think it may be play/wear between the layshaft splines, during the transition from the layshaft being engine-driven to road-driven. (pressure being applied to both sides of the splines rather than one side or the other).

That would explain the low RPM and coasting symptoms we all have?

 

[johnnyd]

That all sounds very expensive to be look at, fixed. Might try gearbox oil on next service. See if that helps at all.

 

[MullyBaby]

This is kinda what I mean, during the transition from engine-driven to road-driven

 

[182_Adam]

That all sounds very expensive to be look at, fixed. Might try gearbox oil on next service. See if that helps at all.

definitely do this...wont do it any harm and may well solve the issue. and yes you're right it could be expensive if a garage looks at it.

 

[182_Adam]

This is kinda what I mean, during the transition from engine-driven to road-driven

this is in the final drive, excessive backlash happen when the gears aren't together tight enough

 

[MullyBaby]

Anybody have any experience with FORTE Diff & Gear Treatment or Holts molyslip gearbox protector? If they do what they say then they might quieten it down but don't know if they are any good?

 

[Hodgins]

mine does this on the overrun, so faint only i can hear it and my friends think im insane lol, had the box rebuilt etc, birchdown said they can hear it but its nothing to worry about, and its been doing it for over a year and box works fine