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Transmission noise
40inches - 6/6/12 at 12:35 PM

Set the rear wheels off the ground to set the Acumen, Bloomin' heck what a row. Can someone have a listen here, I am hoping it's just backlash, because there is no load on the diff.
Just got the money together for the IVA, don't want to have to spend it on a diff or engine


aka Keith - 6/6/12 at 12:47 PM

that sounds just like mine.

when I rebuilt mine, I started the car with the wheels of the ground, and just like you I thought feck me, what cannot be right.

But two years later , it is still gloing strong, so I think that it is just the wheels speeding up faster that the diff when on the power and then slowing down and then back up again etc etc..

Cheers
Craig


Bluemoon - 6/6/12 at 12:53 PM

I bet touching the foot brakes to put a small load on would stop the noise, sounds to me as above, i.e wheels spinning up and taking out the backlash of the diff etc. A slow drive around the block/private road will put you mind at ease..

[Edited on 6/6/12 by Bluemoon]


mark chandler - 6/6/12 at 03:21 PM

Normal, its just the gears chattering with no load, taking the wheels off will help or as above apply a little load with the foot brake.


jacko - 6/6/12 at 03:28 PM

Jack the car up on safe stands get it going in 2nd gear and then use a BIG screw driver one end on the diff and the other [ handle end ] on your ear My God what a NOISE
have a read of this
http://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=170973
jacko

[Edited on 6/6/12 by jacko]


ginger ninja - 6/6/12 at 08:57 PM

Hi mate

there will be a bit of noise from the diff gear backlash, but the noise as best I can tell from the utube clip sounds like what I would expect from the bike gearbox. The dogs which select successive gears are sleeves which slide along the gear shafts in between the gearbox gears.
The gear selection mechanism slides the dogs along until they make contact with one of the gear cogs and lock together, causing that particular cog to turn.
The noise you are hearing is the result of the way this connection is achieved. The driven cogs/gears, and the dogs have a series of square pegs projecting toward each other on the mating faces, a bit like the top of a castle turret on its side.
As the dog is brought into contact with the gear the projections on one fit into the recesses of the other. However, the gaps are wider than the square projections to allow them to engage and disengage. With no load, the gear and dog alternates between load and unload causing the square projections to slide back and fourth within the gaps, colliding with their immediate neighbour to left and right, and generating brown trousers to the uninitiated BEC builder.

It's not as catostophic as it sounds, but prolonged battering can't be good.

Try diving the car over a short distance, whats the worst that could happen !!

I'm only in the next village, Sheffield, if things become really serious

hopefully things will be fine

cheers


40inches - 7/6/12 at 07:13 PM

Thanks everyone, I can put the worry beads away now. I did the old long driver in ear routine, seems to be a combination of diff backlash and gearbox flapping about, loading the wheels all but stopped any noise (and relax). Will take it for a blast on a "private" road when (if it ever) stops raining.
Thanks for all the input, and ginger ninja I never heard Sheffield called a village before


richard thomas - 7/6/12 at 07:26 PM

Totally normal, don't sweat.....


ginger ninja - 8/6/12 at 06:49 PM

"Village" - just being neighbourly.

good to hear engine's OK.


M


"your car is dripping oil"

"thats a relief, - if it stops, it means there's none left in it" !


Northpole - 15/8/12 at 10:05 PM

quote:
Originally posted by 40inches
Set the rear wheels off the ground to set the Acumen, Bloomin' heck what a row. Can someone have a listen here, I am hoping it's just backlash, because there is no load on the diff.
Just got the money together for the IVA, don't want to have to spend it on a diff or engine


I read you comment here as I did have exactly the same problem.
Thanks to you and your video, I did solve my problem, before removing the engine and have a look inside. I only removed the clutch to check it, and it turned out to be fine.
THANKS!