LT95 strange noise?

[Hamersley]

Hi to the Classics,
I have just finished rebuilding my 1977 RR.I did not have the gearbox rebuilt as it seemed ok.
Its has this clicking noise,which comes and goes driving it straight,turn into a LH bend and it disappears but turn into a RH bend and it returns.I have isolated the front axle,cv,s etc. by removing front shaft.There is no difference also clutch in and freewheel noise still there.
I have recorded the noise on my phone but not sure how to put it on the post.
Any ideas very welcome
Thanks Brian

[DoubleChevron]

Hi to the Classics,
I have just finished rebuilding my 1977 RR.I did not have the gearbox rebuilt as it seemed ok.
Its has this clicking noise,which comes and goes driving it straight,turn into a LH bend and it disappears but turn into a RH bend and it returns.I have isolated the front axle,cv,s etc. by removing front shaft.There is no difference also clutch in and freewheel noise still there.
I have recorded the noise on my phone but not sure how to put it on the post.
Any ideas very welcome
Thanks Brian

Speedo cable?

[Hamersley]

Thank you I will disconnect and 🤞🤞

[350RRC]

Hi,

Many moons ago I had nearly the exact same problem except mine has a 350, but still had the LT95 back then.

Clicking noise turning right.................. has to be the LHS CV.

Bought the last new genuine one in Geelong, fitted it, no change. Fitted a whole different LH hub, no change. Doing my head in.

Turned out to be the LHS single pipe at the end of the extractors just touching the chassis rail when turning right.

They are a tight fit each side, LHS being tighter. The engine mounts were getting a bit sad which allowed the whole engine to move just enough to let this happen.

Not saying this is your problem, but with a one way weight transfer something like this is way more likely than something wrong with the LT95.

cheers, David L

[Hamersley]

Thanks David
This should be an easy check and a great win if correct.
my gut says it is in the box especially how the noise is comming in but it’s weird.
cheers
Brian

[Phil 850]

Brian, when you get up to speed you could put the transfer case into neutral and push the clutch in. This should mean that the gearbox is isolated from the drive train and no longer turning and then see if the noise goes/returns.

Phil

[Mercguy]

*Caveat* (This is not an attempt to diagnose your issue)

I once had a similar conundrum.

an amplified whining noise under acceleration after a 6 speed manual box in my 124 coupe.
I was absolutely sure it wasn't the box but the noise was absolutely saying everything otherwise, and to experienced specialists.

It had new engine mounts and geabox mount, and the geabox crossmember had been meticulously strengthened to cope with the tiniest of grabox mount repositioning (6mm forward of previous location and different pilot holes for bolts)

So, with a complete new shifter assembly already thrown in just to ensure it wasn't in linkage bushings etc, and the propshaft checked and balanced (nothing changed) set about absolutely convinced now or never, the box was coming out again.

Took it for a drive and the noise was there, but swapped to passenger side and let mechanic drive, and armed with a stethoscope, decision was "yep, has to be gearbox".

Put up on the hoist, and just as we were getting set to pull the box, suggested another look from underneath with it running.

Mechanic got in, hoist up, in 4th and applied throttle. Said he could hear the whine and as he clutched in I thought I saw something...
asked him to repeat.

and there it was.

the rear gearbox mount (brand new) had a completely invisible separation of the vulcanized rubber from it's alloy encasement, and because of it's design, rotated under load just barely enough to transmit the engine and gearbox vibration straight into the crossmember which essentially was directly behind the shifter inside the cabin.

Replaced the gearbox mount with another.....
noticeably less rotation, and some more violent clutch actions on the hoist confirmed problem was likely connected to the mount - but we still weren't confident.

off the hoist and a test drive around the block with a few "race mode" launches and a couple of highway blats and back into the shop on the hoist to check the mount and everything else underneath.

While the noise was essentially much quieter, there was the faintest bearing noise, and it was soon determined that the tiny little insulating washers between the crossmember and mount were omitted.
reeplaced them and ALL noise was gone.

absolutely nothing wrong with the gearbox - but we scratched our heads for nearly 3 days solid trying to work it out while avoiding the removal of the gearbox (because it's a pain in the ---)

so unless you're convinced beyond measure, and can get it on a hoist and much around with a stethescope probe on all the 'areas of concern' I would hesitate to say it's the box, even if you have a professional standing beside you arguing until they are blue in the face.

Show them this post if they still aren't convinced. then go back to troubleshooting 101 and the process of elimination - because it is the only way to successfully diagnose a noise that "is of concern" but is not able to be easily located or distinguishable from other nearby interefering noises of a similar type.

old mechanics screwdriver stethoscope is a great tool for isolating clunky things inside engines, gearboxes and diffs.

It's just more time consuming and difficult without a hoist.

Hope you find your issue is an insignificant one. (read inexpensive)

[Phil 850]

Hi to the Classics,
I have just finished rebuilding my 1977 RR.I did not have the gearbox rebuilt as it seemed ok.
Its has this clicking noise,which comes and goes driving it straight,turn into a LH bend and it disappears but turn into a RH bend and it returns.I have isolated the front axle,cv,s etc. by removing front shaft.There is no difference also clutch in and freewheel noise still there.
I have recorded the noise on my phone but not sure how to put it on the post.
Any ideas very welcome
Thanks Brian

”removing the front drive shaft” does not isolate the front axle, cv, etc as they are driven by the wheels when moving (unless of course you have free wheeling hubs fitted) which I don’t believe any RR ever had.

Phil

[DoubleChevron]

What I have found works really well for me .... Is to ignore all noises until they become so loud, the source is obvious .... or they fix themselves [biggrin][bigrolf]

[Phil 850]

What I have found works really well for me .... Is to ignore all noises until they become so loud, the source is obvious .... or they fix themselves [biggrin][bigrolf]

Shane, I did this with my 1975 classic.
The LT95 would sometimes give a few “clunks” as I moved off from stationary.
It did eventually cure itself when one of the bolts that hold the low range gear to the centre diff had come loose and fell into the bottom of the transfer case. One of the other bolts then pushed it through the transfer case and onto the road and the noise stopped.

Phil