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After a long trip yesterday (400km or so) Hatchie has developed a problem. I will describe the problem and then tell you what i have ruled out.

Problem is, under load i get a knocking noise that seamingly comes from the drivers side of the car. Only really does it on load and it appears to change frequancy depending on the vehicle speed. Best way to describe the cound itself is it DOES sound like an engine knock like i have heard onece before when my car drank water.

However it is not the motor... during no time when stationary can i simulate the noise and when cruising the noise also goes away. But under even slight load the knock returns.

During steering in either direction the noise does not change pitch of frequancy.

Also when lightly taking off from stationary you can feel something trying to restrict the car from freely moving along.. as if i had a carby flat spot, but the motor is smooth. This can be more easily felt when taking off in 2nd.

Removed the gear box oil to look for signs off metal shards and there was nothing to worry about there.


What i think it isn't...
- I am confident it is not the motor at this stage. (or it would do it when reving or intime with engine RPM and not wheel speed)
- It should not be the wheel bearings because the noise is not constant.
- It is not Inner CV joints (replaced them both this morning)
- Shouldn't be anything with the brakes (The noise would go on and off with brake application if this was the case)
- It's not the tail shaft. (removed that this morning)
- It's not any of the mounts or anything hitting the engine.
- Shouldn't be outer CV's or i would feel it in the steering wheel or it would make the noise more when in full lock.

What it still could be...
- Gear box
- Flywheel
- Clutch

Any ideas or suggestions?
Please keep on topic

Motor is ej22 on adaptor plate running EA82 clutch/box/flywheel

Dave

any chance of it bein related to suspension like castor rod bushes or ball joints

does it make the same noise when driving in 4wd

The noise halves when in 4wd but does not completly go away.

All the front suspension and bushes are seriously no older than 12months old and the car is not my daily driver. So i doubt that. And cos it seams to go with wheel speed it also makes me think otherwise. It's weird that i can not feel it through the body of the car... making me think it has to be something well dampened like the engine/box.

Dave

sounds like it culd be a suspension or driveline thing.

is there any play in any of the wheels at all?


is there any relationship with Engine Temperature?

No play in anything except there was a little in the Tail shaft Uni's which is why i removed that to rule it out. Wheel bearings, CV joints, bushes and all steering and other ball joint components test up fine with normal tests. The noise is also certainly not the usual CV click noise... more of a dull knock. (but not a thud)

Dave

Just to elaberate on what i mean by "load". It doesn;t do it when my foot is on the clutch, when in netraul, when coasting along. Only when there is actually load on the running gear to speed the car up. Im talking very very minor load... granny load.

Dave

last time i had a knock type noise my old man (mechanic by trade) told me to let it develop then bout a week later my diff bracket snapped we found the problem


the other possible problem that comes to mind could it b play in the CV splines into the hub??

Dave , try putting it in gear with the hand brake on nice and tight and with a little throtle release the clutch slightly to put the engine under load and see if you can hear the noise , would be handy to have someone next to the Subi with the bonnet up .

Mike.

sounds like gearbox prob if the noise lessens in low range as there's less . Happened in a suzuki box when i snapped a tooth from the input shaft gear and one connecting gear. Couldn't work it out for ages as the teeth sat in the back of the gearbox and didn't come out in the oil...

Weren't flat changing by any chance? I was...

ok ill take one bet at what this is, from the days of having a EA82t with 27" tyre and more boost, we used to drive around doing skids, which would eventuate us blowing up gear boxes every 12 months or so.

what happens is the crown wheel and pion get weaker and one or the other spits a tooth and then muches the tooth up and breaks more, which is what i would say has happend to your box..

my old MY did this and i had to drive it 30km home sounding like a train going clack clack clack!!!

hope this helps

cheers
bryan

is the noise intermittent or constant knocking ?

i was thinking more along the lines of mounting points like the dreaded captive nuts, or something knocking as engine moves backwards on its mounts during acceleration.

could be but if it is a clack clack clack or clicking noise my bet its the crown wheel and pinion

It's not a captive nut. The noise is constant under any acceleration. It's intime with the wheels moving... the motor doesn't move intime to wheel reveletutions. Everything appears mechanically A1.

Thanks for the ideas... seams obvious now the Gear box is probably at fault.

Dave

Dave,

Once when I replaced a front shaft I removed what I think is called the drive plate?.....the bit with the splines in it to recieve the shaft..... I just tightened the bolts up as tight as i could when i put it back together and that wheel would get the shudders and do strange knocking things at different speeds and gears. I then read they were supposed to be to a certain torque which was well below what i must have tightened them to, plus i would have tightened them unevenly, i tightened them correctly and the problem dissappeared.

rob

Can you put it on a body type hoist and then run it to hear where the sound comes from?

From the description you give it sounds like the same thing I had with my old gearbox, only it was more of a click than a knock. I've heard of a few cars with this lately! Must be that time of year.

dave if u wanna try the 5spd out of my brumby u can i believe it was in the hatch at 1 stage of its life

SUBYDAZZ wrote:Can you put it on a body type hoist and then run it to hear where the sound comes from?

and if u do wanna do that Dave. come speak to me.

or use some jack stands and see wt happens.

im still thinkin u shuld run it in RWD for a little bit to se wt happens to the sound.

if its the front diff it culd go away coz therell be no load out to the wheels (remove both shafts id say)

warped flywheel maybe?

alex

Buddy, based on some of the responces its not sounding good.

I know your trying to avoid lifting out the engine/gbox out again however I hate to say it… you’ll know what it is for sure once you have the bell housing apart. Fingers crossed for you and should you need it I think that I have a d/r 3.9 box ready to go to a good home, just let me know.

After though/additional questions...

1) Is there any way to test to see if your clutch/flywheel are not wearing equally (like across the face, with say the 1 side of it biting harder then the other? You know what I mean?) Would this create a weird knock/shudder as Dave described.

2) Is there any way to test to see if your gear box slowly dying/loosing teeth? I would like to agree with 89rsturbo however as Dave said the gear box oil appeared to be ok, and I would have thought that this would not be the case if a tooth or teeth were being munched.

3) The noise is getting progressively louder?

4) Does it make the noise in reverse?

5) LOL just read “granny loads”.