I have pulled my engine out to try to locate the source of a strange whine which has been occuring when I take my foot off the accelerator. I noticed what appears to be a fine crack underneath the throw out bearing. I have noticed on a spare box I have marks in exactly the same place and I was kind of hoping someone will tell me everything is ok thats normal 😂
EDIT: With the resizing to get the image to upload the area gets hard to see but it is squarish and travels through that area that looks like gear oil is weeping out.
I think u will find its in the thrust beqring
vw54 wrote:I think u will find its in the thrust beqring
The whining noise you mean?
yep
mmm whine in a bearing thats not where i get my wine from 😁
if it occurs when you lift of the throttle it's not the throw out bearing, it should not be spinning until you depress the clutch, it could be in your box
Yeah it is more when I lift off the throttle as I experimented with keeping the revs up while depressing the clutch and it didnt seem to happen then. I guess that means trying out the other box.
The couple of throwout bearings I've had go it's more of a squeal than a whine... similar volume to disk brake squeal, but a bit lower pitch.
Bit late now that the engine is already out, but some tests to possibly try and narrow it down:
1. Sitting stationary... rev in Neutral and let foot off... does it whine ???
2. Sitting stationary... in gear but clutch in... rev it and let your foot off... does it whine ???
3. Car moving, put into neutral... rev it and then let foot off... does it whine ???
4. Car moving, accelerate and then let foot off... keeping it in gear and the clutch out... does it whine ???
5. Car moving, put into neutral and switch off engine... does it whine ???
If it whines for test 1, I'd be thinking maybe the bearing in the gland nut.
If it whines for test 2, throw out bearing.
If it whines for test 3 or 4, box or diff maybe.
If it whines for test 5, I'd be thinking brakes or maybe tyres rubbing or something.
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Thanks Sides I will try those out. I thought of a possibility as well, when I put the cluch back in I eye balled it could this be causing the whine/squeal? just to be safe I will loosen the clutch off and realign it on the engine.
Just spin that thrust bearing by hand and you will know if its stuffed. Besides that, put a new one in anyway, and a new clutch and presure plate.
While you have it apart like that, its easy to replace the consumables.
Also back to my origional question (which I forgot to ask) is there a square casting mark that travels under the thrust bearing or are both my boxes cracked. I will try to upload the photo elsewhere to explain what I mean.
looks like a casting flash.
From a engineering point of view I doubt the box would ever crack like that as the loading on them
does not make any logical sense to cause a crack in that pattern.
71 notchback,
Past owner of, 70 NB, 73 SB and 72 FB TLE
yes that square pattern is normal in the casting
Thanks thats what I was hoping to hear.
Arpspasm wrote:I have pulled my engine out to try to locate the source of a strange whine which has been occuring when I take my foot off the accelerator. I noticed what appears to be a fine crack underneath the throw out bearing. I have noticed on a spare box I have marks in exactly the same place and I was kind of hoping someone will tell me everything is ok thats normal 😂
EDIT: With the resizing to get the image to upload the area gets hard to see but it is squarish and travels through that area that looks like gear oil is weeping out.
HI
it certainly looks like a crack to Me.... but if its on other gearboxes maybe casting marks...??
You can smell gear oil... its a terrible smell...
If it whines when You take Your foot off the accelerator...
still in gear.... clutch throwout bearing etc is not being used...
I would guess something in the gearbox.../diff..
I recommend a bottle of MolyBond or Promar gearbox additive
into the gearbox oil... fresh gearbox oil...
You will see any metal bits on the magnetic gearbox drainplug
make sure You undo the fill plug first [on the gearbox] otherwise You could end up with an oil less gearbox/ transaxle..
do You know how old the gearbox oil is??
and if its filled?? to the filler plug..??
cheers
LEE
Photo shows up fine... LEE
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68AutoBug wrote:it certainly looks like a crack to Me.... but if its on other gearboxes maybe casting marks...??
You can smell gear oil... its a terrible smell...
If it whines when You take Your foot off the accelerator...
still in gear.... clutch throwout bearing etc is not being used...
I would guess something in the gearbox.../diff..
I recommend a bottle of MolyBond or Promar gearbox additive
into the gearbox oil... fresh gearbox oil...
You will see any metal bits on the magnetic gearbox drainplug
make sure You undo the fill plug first [on the gearbox] otherwise You could end up with an oil less gearbox/ transaxle..
do You know how old the gearbox oil is??
and if its filled?? to the filler plug..??
cheers
LEE
[/b]
Photo shows up fine... LEE
The super is a 71 so the gear box may or may not be 40 I have just changed the very thick black gear oil (up to the filler port.) I haven't smelt the sulpher smell. There was a few smallish metal flakes on the magnetic plug but nothing too bad. I have ordered a new throw out bearing just to be safe. Is the a seal behind it that I should be replacing at the same time?
if you clean the area up with thinner's and a paint brush paying attention to the crack, you could fill it with oil and see if you get any seeping from the area, or you could invest in some dye penitrene and check to determine if it is a crack or not, looks like a crack to me.
hellbugged wrote:yes that square pattern is normal in the casting
As Daimo said, it is not a crack, just casting flash.
Wont hurt to replace the seal.
westi wrote:That's mad Alan.
Thanks all, Mat Berry diagnosed from the description that the whineing noise was a loose intake manifold. (and I thought I had torqued all the bolts up correctly 🥲 )
This is a really tough call
I had a good look at a gearbox today and it had casting marks in that same spot.
However, they were straight, clean and dry.
Yours, in comparison are all over the place and look busted. What I really don't like is the bit that looks like a crack radiating away from the bottom right hand corner. It looks traumatised to me.
If it was mine I would give it a really good cleanup and let it sit for a few weeks to see if it weeps. Any sign of wet and it's out of there.
Otherwise,Seeing you have solved the whine, Just chuck it back together and drive it.
