Transmission clunk

[Goosey]

For the first time this morning I noticed what appears to be a clunk when changing lower gears at lowers speeds (it could be I don't hear it at greater speeds!). Tends to be when disengaging the clutch when the car naturally loses momentum. Clutch feels good no issue with the gears, so could it be suspension

Car fitted with BMR lockout, suspension bushes, Steeda progressive springs thus lowered......Yesterday was one of the first days I have really opened it up but I doubt that had an effect !!

I know I have seen threads on this before, but couldn't see I any definitive thoughts.

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[Gibbo205]

This is the transmission thud our cars have, stock its a gentle thud that some notice and some do not.

When you fit BMR CB005 / Diff bushing inserts it changes the thud from a less noticeable thud to a more noticeable clunk.

In short what your hearing is the backlash tolerances on the diff, you will either grow to drive around it or start to not notice it.

Otherwise removal of CB005 and/or diff bushes will resolve it and return it to the thud.

 

[Manders Mustang]

For the first time this morning I noticed what appears to be a clunk when changing lower gears at lowers speeds (it could be I don't hear it at greater speeds!). Tends to be when disengaging the clutch when the car naturally loses momentum. Clutch feels good no issue with the gears, so could it be suspension

Car fitted with BMR lockout, suspension bushes, Steeda progressive springs thus lowered......Yesterday was one of the first days I have really opened it up but I doubt that had an effect !!

I know I have seen threads on this before, but couldn't see I any definitive thoughts.

Is it only after the car has started, I always get a 'clunk' in the morning when I turn out my drive, apparently we sussed out it was the dif fand every car has it when it's cold...

Transmission wise, it's apparently "Meant to sound mechanical", but clunks.... addle:

 

[Gibbo205]

Is it only after the car has started, I always get a 'clunk' in the morning when I turn out my drive, apparently we sussed out it was the dif fand every car has it when it's cold...

Transmission wise, it's apparently "Meant to sound mechanical", but clunks.... addle:

It is just Ford shite quality. A combinations of bad pinion angle, two-piece driveshaft and way too much backlash in the diff from factory.

We also have a single piece flywheel which makes no attempt to dampen such stuff.

Just some of the stuff that annoys me about Ford, to thinking its acceptable to churn out such shit. Its seems they may have addressed it on MY18, but to be frank it should never have left factory like that and Ford will just tell you thats how its meant to be.

Funny how other RWD cars don't seem to have the issue from other manufacturers.

Rant over, you grow to just drive around it or not notice, but you could in theory fix it but there is no 100% cure as such:-

- 1pc driveshaft reportedly can help but they can induce NVH of other kinds.
- Lowering engine mounts, can help as they put the angles more in line, but again tend to induce NVH
- A dual mass flywheel would no doubt greatly help or cure it, Ford have done this on MY18
- Have the diff re-shimmed by a very good diff builder to bring the tolerances tighter, expensive generally.

 

[Manders Mustang]

And to all those points, eff that, if ford accepted liability, like underseal, it'd be a huge (way bigger than Underseal) cost to fix per car, so of course its 'how its meant to be' ;)!

Ah well.. I don't mind it, hardly hear it and the clunk on the gearbox lets me know it's in gear (the screeching a churning lets me know it isn't ;) )

 

[Goosey]

This is the transmission thud our cars have, stock its a gentle thud that some notice and some do not.

When you fit BMR CB005 / Diff bushing inserts it changes the thud from a less noticeable thud to a more noticeable clunk.

In short what your hearing is the backlash tolerances on the diff, you will either grow to drive around it or start to not notice it.

Otherwise removal of CB005 and/or diff bushes will resolve it and return it to the thud.

SO I guess our set up is to stop such movement where as stock is softer and more give ....I guess it's like hitting soft rubber with a hammer v harder rubber, the latter will sound harsher. I know that is a poor example, but I need to know why things happen in my head rather than just accept things. I may not be able to do anything about it, but at least I know and can manage it

 

[Mike Clark]

My Caterham had a very clunky diff, it was a case of TADS (They All Do Sir)

IIRC the worst offenders were taken by their owners to Road & Race Transmissions in Kent, where Phil and his team set them up properly (as in to the :ford: tolerances) rather than what the manufacturers let them out the door with (a lot of the diffs are re manufactured).

 

[Manders Mustang]

My Caterham had a very clunky diff, it was a case of TADS (They All Do Sir)

IIRC the worst offenders were taken by their owners to Road & Race Transmissions in Kent, where Phil and his team set them up properly (as in to the :ford: tolerances) rather than what the manufacturers let them out the door with (a lot of the diffs are re manufactured).

Dare I ask how much that cost per person to 'fix' and I take it, Caterham didn't pay, each owner paid out of their own pocket?

 

[Gibbo205]

Dare I ask how much that cost per person to 'fix' and I take it, Caterham didn't pay, each owner paid out of their own pocket?

People who truly know how to shim differentials are few and far apart, but ideally the diff needs to come out the car, be re-shimmed and put back in. Easily a full days work, so best price would be around £400, but more likely north of £500.

More worth doing if your gonna change your gearing at same time.



P.S. Unless its possible to re-shim in car then a lot cheaper, also a good time to re-fresh the oil in their too, when I dropped mine at 1k miles it was black and full of debris.

 

[v8hgt]

Is anyone in the uk running a one piece prop shaft yet and can directly comment on how this effects the drive line shunt?
I'm considering bringing one over with the mgw shifter before I loose access to my shipping channel, but due to the high cost would love to hear if this is a cure or simply marketing hype. I guess it removes 2cv joints so in theory must have some effect, especially as the joints wear over time.

 

[Gibbo205]

Is anyone in the uk running a one piece prop shaft yet and can directly comment on how this effects the drive line shunt?
I'm considering bringing one over with the mgw shifter before I loose access to my shipping channel, but due to the high cost would love to hear if this is a cure or simply marketing hype. I guess it removes 2cv joints so in theory must have some effect, especially as the joints wear over time.

[MENTION=20104]666mac[/MENTION]has one to fit.

In short, lowering mounts, 1pc shaft, shifter seem to help with it. Dual mass flywheel would probably help as would tightening the tolerances in the diff.

 

[wildcatgoal]

This is the transmission thud our cars have, stock its a gentle thud that some notice and some do not.

When you fit BMR CB005 / Diff bushing inserts it changes the thud from a less noticeable thud to a more noticeable clunk.

In short what your hearing is the backlash tolerances on the diff, you will either grow to drive around it or start to not notice it.

Otherwise removal of CB005 and/or diff bushes will resolve it and return it to the thud.

100% correct. I will also note, after installing Steeda engine mounts, 90% of my clunk is gone. I also lowered the engine .5".

 

[Leeroy]

Things not moved on much since 1965 then....my 289 has a very similar clunk:headbonk:

 

[Mike Clark]

Dare I ask how much that cost per person to 'fix' and I take it, Caterham didn't pay, each owner paid out of their own pocket?

On a new car, Caterham would swap them out if you shouted loudly enough.

If you wanted it done on anything else, then yes, it was a self funded jobbie. Most of the guys would then have the diff tweaked with extras (such as upgrading to limited slip)

The backlash/clunking on my 2007 one wasn't too bad hence I saved my money.

 

[kapiteinlangzaam]

If you shout loud enough (and have a good dealer) in the USA, they will do things about it, as well as the driveline shimmy around 60mph.

However, the chances of getting anything done outside the US is nil, in my opinion.

The only 'good' news is that it doesnt seem to hurt the car.

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