"Bang" from the drivetrain
Discussion
Hello everyone,
I recently noticed ‘bangs’ from the drivetrain on my 95 Chimaera 500. These definitely come from the ‘rear’ in the differential area, not the gearbox. They don't occur in normal driving, only when I suddenly take my foot off the accelerator pedal or when the car “jerks” at low revs (bad driver ;-). An initial visual inspection revealed nothing conspicuous. I searched the forum but didn't really find anything I could build a nice theory on…;-). I have not noticed any permanent noise that would indicate wear of e.g. the differential. The phenomenon is definitely new, I noticed it around the end of last season.....
Does this sound familiar to you? What could I check? Could there be too much play in the drivetrain, causing the driveshaft to kick the differential? If so, where could the play be coming from....?
As always thanks in advance for your help!
Cheers
Sven
I recently noticed ‘bangs’ from the drivetrain on my 95 Chimaera 500. These definitely come from the ‘rear’ in the differential area, not the gearbox. They don't occur in normal driving, only when I suddenly take my foot off the accelerator pedal or when the car “jerks” at low revs (bad driver ;-). An initial visual inspection revealed nothing conspicuous. I searched the forum but didn't really find anything I could build a nice theory on…;-). I have not noticed any permanent noise that would indicate wear of e.g. the differential. The phenomenon is definitely new, I noticed it around the end of last season.....
Does this sound familiar to you? What could I check? Could there be too much play in the drivetrain, causing the driveshaft to kick the differential? If so, where could the play be coming from....?
As always thanks in advance for your help!
Cheers
Sven
however do check driveshaft bolts inc prop-shaft and wheel nuts for security 1st 
Could be driveshaft or diff as others have said.
Could also be something as simple as the rear exhaust mount allowing the two tail pipes to bang on the underside of the boot.
I would check this first. You would think the the rear of the exhaust just "hangs" of the mount.
It is better to adjust the L shaped hanger that goes through the rubber mount so you are actually pushing away from the underside of the boot and not
hanging it there. Hope that makes sense.
Could also be something as simple as the rear exhaust mount allowing the two tail pipes to bang on the underside of the boot.
I would check this first. You would think the the rear of the exhaust just "hangs" of the mount.
It is better to adjust the L shaped hanger that goes through the rubber mount so you are actually pushing away from the underside of the boot and not
hanging it there. Hope that makes sense.
The 'jerking' at low revs is shunting, and it should really be addressed - there are a number of threads on the topic, and I'm far from an expert on it.
But I did learn that having a shunting engine can really take its toll on a diff, and all the parts that connect it to the engine.
If it were my car, I'd get it looked at by a specialist for an assessment, then start looking into the DIY ways to address shunting (a few easy steps around the ignition system and timing) to try to calm the engine.
Any engine will shunt at really low revs (I'd say below 500 rpm), but our RV8s can pull from 850rpm happily, and cruise at 1000rpm under light load.
I'm not an expert, and I certainly wouldn't try to diagnose your car, but I would read around all the possibilities to understand them.
Try not to frighten yourself, but do be prepared to have it looked at if you're not mechanically minded.
But I did learn that having a shunting engine can really take its toll on a diff, and all the parts that connect it to the engine.
If it were my car, I'd get it looked at by a specialist for an assessment, then start looking into the DIY ways to address shunting (a few easy steps around the ignition system and timing) to try to calm the engine.
Any engine will shunt at really low revs (I'd say below 500 rpm), but our RV8s can pull from 850rpm happily, and cruise at 1000rpm under light load.
I'm not an expert, and I certainly wouldn't try to diagnose your car, but I would read around all the possibilities to understand them.
Try not to frighten yourself, but do be prepared to have it looked at if you're not mechanically minded.
PabloGee said:
The 'jerking' at low revs is shunting, and it should really be addressed - there are a number of threads on the topic, and I'm far from an expert on it.
But I did learn that having a shunting engine can really take its toll on a diff, and all the parts that connect it to the engine.
If it were my car, I'd get it looked at by a specialist for an assessment, then start looking into the DIY ways to address shunting (a few easy steps around the ignition system and timing) to try to calm the engine.
Any engine will shunt at really low revs (I'd say below 500 rpm), but our RV8s can pull from 850rpm happily, and cruise at 1000rpm under light load.
I'm not an expert, and I certainly wouldn't try to diagnose your car, but I would read around all the possibilities to understand them.
Try not to frighten yourself, but do be prepared to have it looked at if you're not mechanically minded.
No worries, I just had no time to look after the usual to make it run smoothly. Now it's winter and I only woke it up to get a new windscreen, fix a leaking power steering, repair the air conditioning etc. Will look after spark plugs etc. as soon as all the other issues are fixed.... Shunting is normally not an issue at all but as we all know you need some time to look after it properly…. But I did learn that having a shunting engine can really take its toll on a diff, and all the parts that connect it to the engine.
If it were my car, I'd get it looked at by a specialist for an assessment, then start looking into the DIY ways to address shunting (a few easy steps around the ignition system and timing) to try to calm the engine.
Any engine will shunt at really low revs (I'd say below 500 rpm), but our RV8s can pull from 850rpm happily, and cruise at 1000rpm under light load.
I'm not an expert, and I certainly wouldn't try to diagnose your car, but I would read around all the possibilities to understand them.
Try not to frighten yourself, but do be prepared to have it looked at if you're not mechanically minded.
Hello everyone,
Unfortunately, joints are all in great condtion, the drive shafts as well (these are relatively new) and all possible buffers / bushes also look like new. Don't see where anything could bang somewhere...
There is play in the differential. I can move the wheels by approx. 5 mm (measured on the outer radius of the tyres) before the differential transfers this to the drive shaft. That seems ‘a lot’ to me, what do you say?
Cheers
Sven
Unfortunately, joints are all in great condtion, the drive shafts as well (these are relatively new) and all possible buffers / bushes also look like new. Don't see where anything could bang somewhere...
There is play in the differential. I can move the wheels by approx. 5 mm (measured on the outer radius of the tyres) before the differential transfers this to the drive shaft. That seems ‘a lot’ to me, what do you say?
Cheers
Sven
Loubaruch said:
Apologies for hyjacking your thread.
Changing the subject but you mentioned you had a new windscreen fitted, did it fit well?
Apparently they can be very problematic as several owners have had problems with ill fitting screens.
Who supplied it?
Many thanks!
Windscreen is from shatterprufe, got it from carglass (I think in UK this is AutoGlass). They put it in and said did fit perfectly...Changing the subject but you mentioned you had a new windscreen fitted, did it fit well?
Apparently they can be very problematic as several owners have had problems with ill fitting screens.
Who supplied it?
Many thanks!
Relevant on the differential rear brackets are the two versions, with the brackets changing, GKN to BTR, AND the bolts being too short. When the GKN bolt was used with the BTR, they pulled out of the rear casing threads. A@
Look at the links to the brackets
https://motaclan.com/product/bracket-differential-...
https://motaclan.com/product/bracket-differential-...
Look at the links to the brackets
https://motaclan.com/product/bracket-differential-...
https://motaclan.com/product/bracket-differential-...
Haithabu said:
We did as recommended by you. And indeed there is some play within the bush itself, the inner rubber seems to be sligtly moving. Will replace these and see if it gets better.....
Is it possible to upload video's here....?
It was Sardonicus who originally mentioned the top mount. Is it possible to upload video's here....?
Over the years this bush has generally been the cause of banging and a known fault if the original bush fails.
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