GFROSTY

Hi All,

I have just got my car back from having a new clutch / flywheel fitted and I have noticed coming home this afternoon that the rear diff is making a clonking sound like 2 metal cans are being knocked together which it has never done before.

I can hear it loudly when I am traveling very slow @ about 5-10mph and when the car is moving slowly.

I have had a new paddel clutch fitted together with a billeted flywheel so therefore the gearbox & prop etc have been disconnected. I had also asked the garage to replace all my oils as part of the 63k service.

I know that STI5 rear diffs are a little noisey, I know as mine previously made a slight kocking sound when you moved the wheel back and forth, BUT the clonking sound now is very worrying.

I am being told all that was done to the rear diff was a drive seal replaced as it was leaking a little and to have the oil replaced (with ep90 type I think)

I have tried moving the centre diff switch, but that hasn't made any difference, with me thinking that the load/split might make it better / worse.

So I am after some suggestions as to what might be wrong as although the clonking sounds like a WRC, it didn't make this sound BEFORE I left the car with them.

Comments most welcome, thanks in advance.

GFROSTY

No takers? Surely other STi5 owners could comment on this one?

Fangoria

iTrader: (1)

I have the same on my sti5 - been doing it for about the last 5000 miles

On mine the CV joint at the front left is knackered - so I must sort this out - you sure its the rears and not the fronts

I only get the same type of banging at low speeds - but sounds like its coming from the front/middle

I'm hoping that once I've fitted new drive shafts it will go away

Paddleclutch.............!!! - that wont improve things - I had one and removed it after a while as I had to rev the engine to about 4-5000 to get the car to move forward! - this was an AP 4 paddle clutch, changed to an Organic (my car runs just over 400bhp and the Organic is ok with this)

I also have a lightened flywheel - must admit that I only noticed the sounds once the lightened flywheel was fitted..... - spooky - but it was the same time the front cv joints were failing - changing the fluid should'nt give you this noise

My car has done about 40k miles

GFROSTY

Hi Fangoria, thanks for the reply,

Yes I am sure it is the rear diff as I put my hand under the diff where the propshaft connects to it and slowly rocked one of the wheels back and forth and I could feel the vibration and clonking sound.

Yeah the paddle clutch is a bit of a bugger to get used too on the scooby, I have one in my mk2 escort rally car but generally hold it around 5.5k for launch and don't really have a problem, only when driving around town is is more difficult to use than an organic one.

Now I am wondering if by having a lighter flywheel & paddle clutch increases the noise from the rear diff?...

My car has just had a full service at 63k, and cv joints are ok.

What oil do you use in your diff, Castrol syntrax 75/90?

Will a paddle clutch make the diff more susceptible to damage over time, after all when the clutch enages now it launches the car forward with a clonk. I get the feeling that there is a little play in between when the diff and the drive shafts start to turn the wheel, but I have been told everything is tight.

On another note, what have you done to get 400bhp? and what sort of torque figure do you now have?

Fangoria

iTrader: (1)

I think the noise thing is a red herring!

75/90 Silkolene - changed every 25000 miles - should be every 40,000 kms per the Japs

Paddle clutch will gradually kill everything - gearbox, engine mounts, driveshafts, diff............ I had one in a Cosworth also and costly. I changed the plate on the Scoob very soon so as not to cause any lasting damage - though I think it destroyed the CV joints!!! prematurely

403 bhp and 355lbs torque -(Well Lane) 389 and 335 at Power Engineering - but then the results can vary day in day out!

A long process I'm afraid - but now pretty easy to get to 400-450bhp in the Scoob community

VF 22MD195 Turbo - Turbo Dyanmics
Link ECU and upgrades
740cc injectors
Arrow Rods
High compression Omega pistons
Modified oil system
HKS Hyper
3 inch Hayward downpipe
sti uprated turbo inlet pipe
Gruppe S headers
Walbro Fuel pump
FSE fuel pressure Regulator
AP organic clutch
3 port boost solenoid
3 Bar Maf sensor
APS fron mounted intercooler and pipes
APS cold air kit

Sure that there a few other bits

And of course suspension and brakes and stereo and laser devices!!

Now have a bigger turbo and will be sorting out 3d mappable ERL water injection in the near future - plus have just got racing spark plugs as the std ones are no good for that sort of power - just cost me £150 for plugs!!

btw I run Shell Optimax and a full bottle of NF Octane Booster with 'every' fill up