Gearbox noise (with video)

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Phil-1954
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Gearbox noise (with video)

Post by Phil-1954 »

Hello all,

I have recently joined the list to get some thoughts on my suspected 'shot' (well 95% sure) gearbox.
I have made a short video showing the noise I'm getting. It's a regular 'thrumming' type of sound that is revolution dependant.
https://youtu.be/hDsMza4q-Io
Video shows noise in Top gear, 2nd and 3rd.

Before I get a reconditioned gearbox, I just wondered if anyone had any ideas on what in the gearbox has gone?
Reconditioned prices currently range from around £600 to an eye watering £800.
So far I have been looking at 'Heathrow Transmissions', 'ESM Morris', 'Bull Motif', 'Charles Ware' There are varying comments on all those named, with one in particular looking best to avoid.

Any thoughts on any other current good companies are welcome, as a lot of recommendations thrown up in searches are several or more years old now.

It's far 1098cc 1967 2 door Saloon (ribbed box obviously)

Phil
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Phil T
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mowogg
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Re: Gearbox noise (with video)

Post by mowogg »

It will be really interesting to hear what others think, but are sure sure its the gearbox? It sounds to me that this is more related to engine revs, which might point you elsewhere

I would start checking engine and gearbox mounts to make sure this is not the issue. I would also have a look at the exhaust(check for clearance) and the top steady mount before looking at a gearbox replacement.

Might be worth checking its not the dynamo too, by taking off the fan belt for a test run
JOWETTJAVELIN
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Re: Gearbox noise (with video)

Post by JOWETTJAVELIN »

If the gearbox is still working, I would not touch it.
newagetraveller
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Re: Gearbox noise (with video)

Post by newagetraveller »

I would start by checking oil level in gearbox and oil level in back axle if you have not already done so.
les
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Re: Gearbox noise (with video)

Post by les »

A long shot but if you’ve fitted a 2 blade radiator fan, suspect that, caught me out once, fitted to a Mini.

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Re: Gearbox noise (with video)

Post by Phil-1954 »

All,
I have just typed a long reply to the helpful suggestions, and now something has occurred to me!
So not being rude, but rather than put matchsticks under my lids to alter what I have written I'll get back tomorrow.

Phil
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IslipMinor
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Re: Gearbox noise (with video)

Post by IslipMinor »

Picking up the thought on the fan, and before doing anything else, is it cracked or anything like that?

The in-gear speeds all relate to same engine speed, 3,300/3,400 rpm. If the gearbox is in neutral, and the engine speed increased to the same speed does the noise occur? If it does, remove the fan belt and try again.

1st gear is generally noisy nayway, but the equivalent speed is 15 mph. Is the same drumming noise audible at 15 mph in 1st?

What happens if you continue to accelerate to higher engine speeds in each gear? Does the noise continue or fade away?

P.S. What is the 'App' that gives the speed and GPS coordinates at the bottom of the screen - very nice!
Richard


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Re: Gearbox noise (with video)

Post by oliver90owner »

Richard,

My guess is that it is a down-loaded play-back from a dash cam with all, or some, of the bells and whistles?
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geoberni
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Re: Gearbox noise (with video)

Post by geoberni »

I cannot imagine anything gearbox/transmission related that would cause such a rhythmic sound at a constant speed.
I would expect the sound to be constant pitch, varying with speed, but constant when at a steady speed.

Reminds me of something more wheel/tyre related...........
Basil the 1955 series II

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geoberni
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Re: Gearbox noise (with video)

Post by geoberni »

oliver90owner wrote: Sun Oct 06, 2019 10:08 am Richard,

My guess is that it is a down-loaded play-back from a dash cam with all, or some, of the bells and whistles?
I have a similar set of functions on the Dash-Cam in my Modern; although not being a very expensive one, I can't add a complete Reg No to mine as it only allows a Chinese/Hong Kong layout :roll: :lol:
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Re: Gearbox noise (with video)

Post by Phil-1954 »

All,
I'll get back to the gearbox, but Dashcam is a "Nextbase 512G". It also will show reg number.

Phil
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Phil-1954
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Re: Gearbox noise (with video)

Post by Phil-1954 »

Hello,
Very interesting replies! I'll cover each point hopefully.
But my main three reasons behind the gearbox being the culprit were:

Firstly:- It seems to occur at a consistent engine rev speed in each instance.
(All speeds mentioned are GPS accurate on dash-cam - a 'Nextbase 512G')
I don't know the engine revs used, but in 4th (ratio of 1:1) it clearly starts at 56mph
3rd is 1.412, which is a ratio of 0.708 to 4th gears 56mph, so 4th's 56mph becomes 39mph
2nd is 2.172, which is a ratio of 0.650 to 3rd gears 39mph, so 3rd's 39mph becomes 25mph
The speeds worked out above in 2nd & 3rd are in fact those when it occurs on the road as well (26 & 39).
(Diff ratio omitted as irrelevant as same for all)

Secondly: First gear has recently started crunching when leaving 1st and before changing up into 2nd. In other words if I go 1st out into neutral it will crunch. So box definitely not healthy.

Thirdly The gear box lever has become stiffer whilst changing gears.
Points 2 & 3 could be unrelated to the main trouble admittedly.

As for the replies: Yes mowogg, the Engine & box mounts DO both want replacing admittedly, but it seems and feels a precise resonance issue rather than a broader vibration issue that I would expect from mounts. I will do them before ordering any g/box though.
I have an alternator which has good bearings and the exhaust is not rubbing and no pipe supports are missing.
Newagetraveller : (oil level) I haven't checked yet, but that was going to be done before hand anyway. :D It hasn't lost oil though - it's dry underneath, (this all assumes it had oil when purchased 900 miles ago!)
Les: (2 blade fan) I have a normal Moggie fan fitted - or at least it's not 2 bladed, but will check for looseness.
IslipMinor: I realised last night that I had not carried on accelerating past where it started, this could tell a lot and will do.
geoberni: I too had originally suspected a defected or bulging rear tyre, it certainly has the same feel and noise, but it would be tied to road speed then, not engine revs, also the frequency is not that expected at 56 mph (it's slower than what a tyre would produce at relevant speed)
I'll keep the list informed, but my tame mechanic (long suffering son) is tied up next week.
I was 95% sure on the g/box, but now much less so.

Thanks all for the responce.

PS: Dashcam was a requirement by the insurers (Admiral, classic car) I've been very pleased with it as its good at nights as well. Now superseded by another model- like everything else, its all about £££
Phil
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Phil T
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paul 300358
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Re: Gearbox noise (with video)

Post by paul 300358 »

Interestingly, my 1098 makes the same noise at the same speeds, just not as loud. It's not the fan as mine is electric. Not the prop shaft u/j's. I wondered if its the gearbox input shaft bearing. I should also say that my exhaust is not rubbing, the engine mounts are good and the tyres are new.
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Re: Gearbox noise (with video)

Post by jagnut66 »

Dashcam was a requirement by the insurers (Admiral, classic car)
Hi,
As a side issue, why are Admiral insisting you have a dashcam? Are you a young driver or do they insist that everyone they insure has one?
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
Phil-1954
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Re: Gearbox noise (with video)

Post by Phil-1954 »

Hello Mike,
I wish I was a young driver actually - my age is in my user name :D
I was asked if I had a dash cam to which I replied yes, and my quote was based on that. The policy states that if it's not used and its evidence could have proved critical, I may be liable for extra costs, or words to that effect
So if you get a lower premium because of the cam, you need to use it. How much I saved over not having one I'm not sure though now.
I'll shop around more next year anyway.
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Phil T
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oliver90owner
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Re: Gearbox noise (with video)

Post by oliver90owner »

I have a nextbase (can’t remember the model) and it is quite good. I also have a cheapie, non recording of data such as location coordinates, acceleration, g forces on cornering/braking, etc. fitted to the rear. It cost me a tenner from epay and included a memory card - the power extension lead wasn’t far off the camera cost!.

The nextbase was rather more costly. Their biggest problem is battery life. I’ve changed it once and it will soon need changing again, I think.

Peace of mind if something untoward occurs. One needs to adhere to traffic signals and speed restrictions as these details can be used by plod if necessary, but one can always delete anything - as long as it is before any major occurrence (eg pedestrian jumping out in front). People have been convicted of offences, identified after another incident has meant seizure of their dash cam by police.

I’ve not bothered to insure around the use of it - that could work against one in the case of a claim.
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Re: Gearbox noise (with video)

Post by kennatt »

could be the diff whining, sometimes difficult to locate area of sound,does it go off when throttle eased,usual sign of diff noise
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Re: Gearbox noise (with video)

Post by jagnut66 »

People have been convicted of offences, identified after another incident has meant seizure of their dash cam by police.
Since we all 'infringe' on speed limits occasionally I think what you've just said is a very good reason not to get one.
Either that or delete after each journey 'just in case' and hope you haven't 'infringed' just before it (possibly) is seized as evidence for something else...…………
I like to relax when driving, for any advantages it might have, I don't think it's worth the risk.
It would just be another distraction from the road ahead, worrying / trying to see if you are 'infringing'...….. ironically that may even cause an accident...….
Best wishes,
Mike.
1954 Series 2: 4 door: "Sally" -- Back on the ground with (slave) wheels and waiting to be resprayed......
1970 Triumph Herald 1200: "Hetty" -- Driven back from Llangollen in Wales (twice.....)
Phil-1954
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Re: Gearbox noise (with video)

Post by Phil-1954 »

All,
Dash-cams
Firstly my motivation to get it a couple of years back, was protection against the menace of staged accidents for insurance scams. It doesn't distract, its out of the way, and the screen goes blank while driving. I just leave it to quietly recording away. Moggie's seem to lend themselves to speed limit driving anyway.( Having said that I broke the speed limit in the video when accelerating in 3rd gear @ 39mph, not realising at the time)_ :oops: . If you have a crash the Police will take your cam, and despite you supposedly deleting everything, getting it all back is surprisingly easy, especially the latest deletes.

Gearbox:
I've yet to try 'IslipMinor's' suggestion, but it does appear engine rev related as he mentions, which the maths above in one of my posts tends to support, rather than speed or axle related. I do need a clutch change anyway sometime before next spring, a mechanic has also confirmed that, so while the box is out I can check the main input bearing as 'paul300358' suggests and I also favour, and also do the mounts. If the box is the culprit I just leave it up on stands till I get one, annoying as it's my sole transport now, but not the end of the world.
Further diagnosis / guessing will follow when I know if I can drive out of the sound by going quicker, and if present in first gear at the expected speed, so that's my next step when weather permits, and I'm up to it. (Quite what that will prove I'm not sure yet)
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Phil T
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Phil-1954
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Re: Gearbox noise (with video)

Post by Phil-1954 »

All,
I had totally forgotten, but my friend who was passenger just reminded me: It stops if you knock into neutral when it's doing it (with clutch released, ie: just coasting)
We only done that test in 4th gear, but it definitely stopped.
(right ............... were did I leave my head, and I'm not talking cylinder)
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Phil T
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