Clonking chimp
Discussion
Been getting an occasional clonking noise and judder from the back of my 450 chimp when disengaging the clutch and pulling away for the last couple of k miles (18k miles total).
Coming back from Rockingham yesterday (not sure its right watching ASCAR V8s and CART500 cars walling themselves for our pleasure, still
) in miles of stop/start traffic the clonking and judder happens every time; kindof as if the rear brake calipers are binding, only expensive, like worn bushes or a problem at the diff.
Whilst I am fairly well infantile in mechanical knowledge my guess is a diff problem as the slower I ease the clutch out and move off the worse the clonk, but confusingly its only noticeable moving off in first gear, not up or down the box..
In the worst case how much would a Chimarea 450 diff rebuild be and who in the south-east would be recommended to look into this ... Thames Valley, Tower View ?
My dealer will not be getting a look in as they "diagnosed" it as loose exhaust baffles at the last service and "happend" to have a spare Chimp exhaust in stock at the time they were tying to sell
- yeah right.
Coming back from Rockingham yesterday (not sure its right watching ASCAR V8s and CART500 cars walling themselves for our pleasure, still
) in miles of stop/start traffic the clonking and judder happens every time; kindof as if the rear brake calipers are binding, only expensive, like worn bushes or a problem at the diff. Whilst I am fairly well infantile in mechanical knowledge my guess is a diff problem as the slower I ease the clutch out and move off the worse the clonk, but confusingly its only noticeable moving off in first gear, not up or down the box..
In the worst case how much would a Chimarea 450 diff rebuild be and who in the south-east would be recommended to look into this ... Thames Valley, Tower View ?
My dealer will not be getting a look in as they "diagnosed" it as loose exhaust baffles at the last service and "happend" to have a spare Chimp exhaust in stock at the time they were tying to sell
- yeah right. quote:
Been getting an occasional clonking noise and judder from the back of my 450 chimp when disengaging the clutch and pulling away for the last couple of k miles (18k miles total).
Coming back from Rockingham yesterday (not sure its right watching ASCAR V8s and CART500 cars walling themselves for our pleasure, still
Whilst I am fairly well infantile in mechanical knowledge my guess is a diff problem as the slower I ease the clutch out and move off the worse the clonk, but confusingly its only noticeable moving off in first gear, not up or down the box..
In the worst case how much would a Chimarea 450 diff rebuild be and who in the south-east would be recommended to look into this ... Thames Valley, Tower View ?
My dealer will not be getting a look in as they "diagnosed" it as loose exhaust baffles at the last service and "happend" to have a spare Chimp exhaust in stock at the time they were tying to sell
Diff mounting busges would be my first guess too. They need to be checked and tightened at every service. Could also be worn/loose CV joints, or wear inside the diff, although all of these are less likely. Could also be the exhaust knocking in something as the engine twists under load (which would be more obvious in first gear), either caused by a misaligned exhaust or knackered engine mounts.
If you're looking for somewhere good to look after this around the North London area, I recommend Tower View. I've used them for the past eight years or so and I'm very happy with them.
Cheers,
Peter Humphries (and a green V8S)
I reported in an S thread some months ago a very similar problem. Many suggestions as to the cause was offered, but could not find the problem.
Jacked the car up one weekend to start serious investigations only to find the wheel nuts on n/s rear wheel were only just better than finger tight??
Removed wheel and checked everything very carefully, re-fitted wheel and did proper final check of nuts with wheel on ground. Problem solved.
Q. Has anybody removed your wheels recently? Did they perhaps fail to torque wheel nuts properly on refitting?
Jacked the car up one weekend to start serious investigations only to find the wheel nuts on n/s rear wheel were only just better than finger tight??
Removed wheel and checked everything very carefully, re-fitted wheel and did proper final check of nuts with wheel on ground. Problem solved.
Q. Has anybody removed your wheels recently? Did they perhaps fail to torque wheel nuts properly on refitting?
Straight out and checked the wheel nuts, nope I'm not getting away that easy >sigh<.
But a great idea from the missus had me pushing the car up and down the road like a fool with her grovelling around the undercarriage locating the judder and a neighbour with a 911 looking on with amusement. Its one of those bonding moments between man and machine which you just don’t get with a new porker.
Apparently at a slow walking pace it starts to "donk, donk, judder" which comes from the rear axle area inboard of the wheel (my translation) and is not the exhaust.
But a great idea from the missus had me pushing the car up and down the road like a fool with her grovelling around the undercarriage locating the judder and a neighbour with a 911 looking on with amusement. Its one of those bonding moments between man and machine which you just don’t get with a new porker.
Apparently at a slow walking pace it starts to "donk, donk, judder" which comes from the rear axle area inboard of the wheel (my translation) and is not the exhaust.
Hi,
Something very similar happened with my 450. The noise was an irregular clunking in first and in reverse. Mine is R reg so it is the later diff. Initially lots of pointers to diff mounting bolts so I left the car with my local mechanic for 2 weeks and he was going to change the mounting bolts. However, he had a look and decided the noise was coming from the diff. He opened the diff up and there a two plates (planet plates I think the're called) and they were too far apart. He tightened them up, refilled with new oil etc and now it is like a new car. It feels soooooooo good. So after all the phone calls etc and discussions the problem was finally located. and fixed.
Paul
Something very similar happened with my 450. The noise was an irregular clunking in first and in reverse. Mine is R reg so it is the later diff. Initially lots of pointers to diff mounting bolts so I left the car with my local mechanic for 2 weeks and he was going to change the mounting bolts. However, he had a look and decided the noise was coming from the diff. He opened the diff up and there a two plates (planet plates I think the're called) and they were too far apart. He tightened them up, refilled with new oil etc and now it is like a new car. It feels soooooooo good. So after all the phone calls etc and discussions the problem was finally located. and fixed.
Paul
Both good and bad news.
The good news is that I happend by Thames Valley Racetech at lunchtime to talk about some upgrades and mentioned the problem. Hmmm the techies didnt like the noise and it went straight onto the ramp (wow !).
The bad news is that with the clonking coming from an apparently unusual BTR Cone type diff (on a '99 450) the oil is let out and is found full of metal with the possability of some larger bits floating about.
Plan A is to open it up for a looksee (hope for a bit of wear caused by misadjusted plates or whatnot) Plan B is to fit a recon hydratrack unit for £450
The good news is that having done about 4,000 miles since it started (just before the last service) I have avoided x-ing out the powertrain and myself with a seized diff on the planned trip to the Nurburgring this weekend !
The good news is that I happend by Thames Valley Racetech at lunchtime to talk about some upgrades and mentioned the problem. Hmmm the techies didnt like the noise and it went straight onto the ramp (wow !).
The bad news is that with the clonking coming from an apparently unusual BTR Cone type diff (on a '99 450) the oil is let out and is found full of metal with the possability of some larger bits floating about.
Plan A is to open it up for a looksee (hope for a bit of wear caused by misadjusted plates or whatnot) Plan B is to fit a recon hydratrack unit for £450
The good news is that having done about 4,000 miles since it started (just before the last service) I have avoided x-ing out the powertrain and myself with a seized diff on the planned trip to the Nurburgring this weekend !
quote:
Both good and bad news.
The good news is that I happend by Thames Valley Racetech at lunchtime to talk about some upgrades and mentioned the problem. Hmmm the techies didnt like the noise and it went straight onto the ramp (wow !).
The bad news is that with the clonking coming from an apparently unusual BTR Cone type diff (on a '99 450) the oil is let out and is found full of metal with the possability of some larger bits floating about.
Plan A is to open it up for a looksee (hope for a bit of wear caused by misadjusted plates or whatnot) Plan B is to fit a recon hydratrack unit for £450
The good news is that having done about 4,000 miles since it started (just before the last service) I have avoided x-ing out the powertrain and myself with a seized diff on the planned trip to the Nurburgring this weekend !
Bummer.
Tell them you want them to use Securicor to courier the diff to the rebuilders (if it needs to go away). They'll go green 'cos mine took 3 weeks to find it's way back to them (picked up last week, now running rebuilt diff in)
quote:
Did a search on Hydratrack and established that Mr GreenV8s hates it and most other folk recon its not worth mo' money.
Whats the upside; would it help or hinder spirited driving around country lanes ?
Hinder, bargepole job, recommend you go for a standard friction plate locker, also a lot cheaper!
Cheers,
Peter Humphries (and a green V8S)
Thanks Peter, but if I cant rescue the current unit I may haveto learn the hard way and put the next 20k miles down through Hydratrack and see how I feel at the next diff replacement in 2005.
Unless "the hard way" involves an increased chance of spinning off a corner ... if one wheel is already slipping why would you want more power to the other wheel ?
Unless "the hard way" involves an increased chance of spinning off a corner ... if one wheel is already slipping why would you want more power to the other wheel ?
quote:
Well it doesnt look good; a rebuild of my BTR friction diff will be £565, or I could have a recon Hydratrack for £450 and apparently less driving pleasure ... what does the audience think ?
£115 difference..... not massive.. considering the labour costs of the replacement itself I'd spend the extra and get what was designed for the car and is deemed the better option.. if it was £250-300 I might agree but £115....
I caved and have taken the Hydratrack. I know its foolish 
to try and save a bit on a big job but apparently I need some new S02's on the back and the cash saving will score a couple I have located at a reasonable price.
Plus I'll be able to report back with on the difference between a friction and hydra diff.
to try and save a bit on a big job but apparently I need some new S02's on the back and the cash saving will score a couple I have located at a reasonable price. Plus I'll be able to report back with on the difference between a friction and hydra diff.
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