Slight clunk under floor

genpk · 21st February 2018, 07:20

Getting a small clunk on my 75 diesel almost under my feet or around the accelerator pedal assembly.
Car drives fine, no clunk, knocks etc when driving, even quiet over speed bumps
Before everyone says it’s worn lower wishbone bushes or lower engine mount, just done both thinking it was one of those but the issue still remains
The issue seems to occur when decelerating and the auto is coming back down through the gears and you feel a small clunk in the floor area.
Dosn’t seem to have any relationship when braking nor when accelerating just when there is some sort of torque on the motor changing back down
I have also replaced the hydramount and top engine mount a few months ago so they should be fine?
Ideas ?

Lord of Hog · 21st February 2018, 07:32

Exhaust hangers getting a bit tired?

rustymotor · 21st February 2018, 08:50

Hi, change ATF perhaps..

genpk · 21st February 2018, 09:08

The auto appears to be working fine, changes all smooth, fluid changed a couple of months ago.
As said, i only feel the small clunk in the floor pan area when the auto is going down back into second gear (decelerating)
Fine when taking off and accelerating and braking.
As for exhaust brackets, I’ll have a look, that is a good point to look at .

stevestrat · 21st February 2018, 09:11

Quote:

Originally Posted by Lord of Hog

Exhaust hangers getting a bit tired?

Had that myself, the exhaust dropped just enough to bring the tunnel cross braces within range of normal movement.

Groundsman Willie · 21st February 2018, 10:30

Quote:

Originally Posted by stevestrat

Had that myself, the exhaust dropped just enough to bring the tunnel cross braces within range of normal movement.

This would be my bet too

genpk · 22nd February 2018, 10:27

Got the car up on ramps today, had a look at the exhaust hangers, all seemed fine, plenty of clearance all around the heat shield , cross braces, rubbers looked fine etc.
Checked steering rack , all tight.
Think the only way I might be able to see what’s going on would be up on a hoist
and start the engine, foot on brake and shift from park to drive and have someone underneath.
Unfortunately I don’t have a hoist so unless the tiny noise gets worse probably not worth the effort !!
Only thing that has a bit of give in it is the flexible joint before the cat but looked fine.

genpk · 9th March 2018, 14:54

Took the car to a local suspension specialist re the slight noise on braking and take off and they could not locate the source of the noise.
Everything they tested seemed fine.
There suggestion was to see if it gets worse as the car is driving fine and nothing obvious seems worn. Gotta love these cars little quirks !!

genpk · 15th August 2018, 07:54

Still had the small clunk on acceleration and deceleration.
Taken to my local mechanic who reckons they have traced it to tge hydramount.
I stated i had put a new one in under 12 months ago so should be ok.
No sign of any leakage ftom the hydramount and the rubber looks fine but ive asked them to have a look anyway.
Im wondering if it has worked loose and on the diesels theres an aluminium spacer which sits under the mount and lifts the mount up so it fits the duesel engine.
Hoping that the spacer might have worked loose and is moving?

ZedTeeT · 15th August 2018, 08:58

Sounds like it could be in the drive train somewhere, drive shaft, CV joint? Do they have a bearing supporting the os drive shaft?

21st February 2018, 07:20	#1
genpk Posted a thing or two Rover 75 Saloon MGZT Join Date: Jul 2012 Location: Perth, AUSTRALIA Posts: 1,662 Thanks: 3 Thanked 461 Times in 299 Posts	Slight clunk under floor Getting a small clunk on my 75 diesel almost under my feet or around the accelerator pedal assembly. Car drives fine, no clunk, knocks etc when driving, even quiet over speed bumps Before everyone says it’s worn lower wishbone bushes or lower engine mount, just done both thinking it was one of those but the issue still remains The issue seems to occur when decelerating and the auto is coming back down through the gears and you feel a small clunk in the floor area. Dosn’t seem to have any relationship when braking nor when accelerating just when there is some sort of torque on the motor changing back down I have also replaced the hydramount and top engine mount a few months ago so they should be fine? Ideas ?

21st February 2018, 07:32	#2
Lord of Hog Gets stuck in Rover 75 2.5 V6 in Wedgwood Blue Join Date: Dec 2015 Location: Felbridge, East Grinstead Posts: 982 Thanks: 250 Thanked 294 Times in 206 Posts	Exhaust hangers getting a bit tired? __________________ Conformity is not morality. Consensus is not truth.

21st February 2018, 08:50	#3
rustymotor Posted a thing or two Rover 75 Tourer Join Date: May 2017 Location: Hull Posts: 1,848 Thanks: 216 Thanked 432 Times in 340 Posts	Hi, change ATF perhaps.. Last edited by rustymotor; 21st February 2018 at 08:55..

22nd February 2018, 10:27	#7
genpk Posted a thing or two Rover 75 Saloon MGZT Join Date: Jul 2012 Location: Perth, AUSTRALIA Posts: 1,662 Thanks: 3 Thanked 461 Times in 299 Posts	Got the car up on ramps today, had a look at the exhaust hangers, all seemed fine, plenty of clearance all around the heat shield , cross braces, rubbers looked fine etc. Checked steering rack , all tight. Think the only way I might be able to see what’s going on would be up on a hoist and start the engine, foot on brake and shift from park to drive and have someone underneath. Unfortunately I don’t have a hoist so unless the tiny noise gets worse probably not worth the effort !! Only thing that has a bit of give in it is the flexible joint before the cat but looked fine. Last edited by genpk; 22nd February 2018 at 10:29..

15th August 2018, 08:58	#10
ZedTeeT Gets stuck in MG ZT-T Join Date: Feb 2016 Location: Horsham Posts: 874 Thanks: 197 Thanked 239 Times in 207 Posts	Sounds like it could be in the drive train somewhere, drive shaft, CV joint? Do they have a bearing supporting the os drive shaft? __________________ My garage. 03/53 MG ZT-T+ CDTi auto in XPG. 232k and much to do! 21/21 MG ZS ev. Daily. 85/C Capri 2.8i Special. Mine 29+ years. 82/X Talbot Tagora SX V6. Restoration project. 11/11 Hyundai I Load CRDi. Van....... nuff said.

21st February 2018, 09:08	#4
genpk Posted a thing or two Rover 75 Saloon MGZT Join Date: Jul 2012 Location: Perth, AUSTRALIA Posts: 1,662 Thanks: 3 Thanked 461 Times in 299 Posts	The auto appears to be working fine, changes all smooth, fluid changed a couple of months ago. As said, i only feel the small clunk in the floor pan area when the auto is going down back into second gear (decelerating) Fine when taking off and accelerating and braking. As for exhaust brackets, I’ll have a look, that is a good point to look at .

9th March 2018, 14:54	#8
genpk Posted a thing or two Rover 75 Saloon MGZT Join Date: Jul 2012 Location: Perth, AUSTRALIA Posts: 1,662 Thanks: 3 Thanked 461 Times in 299 Posts	Took the car to a local suspension specialist re the slight noise on braking and take off and they could not locate the source of the noise. Everything they tested seemed fine. There suggestion was to see if it gets worse as the car is driving fine and nothing obvious seems worn. Gotta love these cars little quirks !!

15th August 2018, 07:54	#9
genpk Posted a thing or two Rover 75 Saloon MGZT Join Date: Jul 2012 Location: Perth, AUSTRALIA Posts: 1,662 Thanks: 3 Thanked 461 Times in 299 Posts	Still had the small clunk on acceleration and deceleration. Taken to my local mechanic who reckons they have traced it to tge hydramount. I stated i had put a new one in under 12 months ago so should be ok. No sign of any leakage ftom the hydramount and the rubber looks fine but ive asked them to have a look anyway. Im wondering if it has worked loose and on the diesels theres an aluminium spacer which sits under the mount and lifts the mount up so it fits the duesel engine. Hoping that the spacer might have worked loose and is moving?