Member
SupporterHi All,
So I've got my suffix B gearbox on the bench for the second time. (-sigh-)
It had a rumble and unknown history so its been out and had all things that were broke/ worn replaced and put it all back together. Problem is, I haven't actually driven any S3 for real so I don't actually know what to listen for. Before it came apart I ran all its gears through the full drive train while it is on blocks it definitely didn't make this type of sound so here goes:
Reverse is noisy! How noisy should it be?
Both the reverse gear itself and the 1-2 synchro it mates with are new, but when the gearbox is fully assembled reverse sounds like, well, that clatter sound when you haven't quite got a gear selected ... but it is definitely in gear clean.
On the bench, I can reproduce most of the clatter:
- all transfer box etc is still attached.
- removed bell housing
- removing the layshaft
- selecting 4th (I think? - to connect to forward syncho and drive the mainshaft)
- selecting reverse (i.e. slide the reverse gear to meet the 2nd synchro)
- checking it is engaging cleanly.
- temporarily close the bellhousing
- spin the mainshaft
- i.e without the layshaft its just the mainshaft driving the idle reverse gear.
...and there it is clattering away like I can't drive a manual... Its only the new reverse gear contacting the new 1-2 synchro with zero load (not even the layshaft).
- Will these things 'wear in'
- I was careful (I thought) with getting the correct parts. Teeth lined up old vs new etc. I didn't see many ways to get the wrong parts though.
- Are the cut of my new gears a variation of ..rubbish?
Ideas welcome - especially if they save me going all the way back and sticking the old gears back in - or give me confidence that that is the next step anyway!
Cheers all, and may my dilemma give you entertainment !
RoverLord
It is almost impossible to judge whether it is just normally noisy or too noisy from your description.
Because it is straight cut, not helical, reverse will always be very noisy compared to the other gears, and the noise level will be increased by misalignment (i.e. either the reverse shaft or the main or layshafts misaligned due to slop on bearings or worn or damaged casing.
Running it either dry or with low visscsity oil will mmake it noisier.
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
Member
SupporterThanks John - especially for raising the topic of viscosity of oil. The cheap stuff I have(had) in there was way thinner than what came out of it originally. I'm thinking I'm just a bit sensitive to stuffing it up and it actually is how it normally is - especially with the straight cut gears.Originally Posted by JDNSW
I saw your note on Sat and by the end of Sunday had it all buttoned up re-installed. She is still on blocks so I ran reverse with full drivetrain attached and I think it sounds normal now.. i.e. when the revs get up is becomes more of a wine than a clatter which seems about right. I'm going with its a 'nothing to see here' LR special along with maybe some soundproofing later on :-)
Even when fully assembled on the bench and being pushed to about 1200rpm (via a drill on the mainshaft) the sound was there but it isn't one that sounds of misalignment - i.e. its still 'smooth' , no 'grind' and really is just those straight cut gears slapping together.
Well thats my story and I'm sticking with it because I'm over cutting gaskets and doing prop-shaft bolts :-)
RoverLord
Note that the specified oil is EP90, the same as the axles and transfer case and steering box. A modern low viscosity gearbox oil is likely to be noisier, even if the driving experience is better.
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
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