Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 (edited) I overtook a car on the way to work this morning, wasn't full throttle because of the weather, but there was a series of loud bangs and vibrations from the back of the car, as soon as i heard it I backed of, it seemed ok so i first thought (or rather hoped) it was just the rear wheels slipping on ice, but when i got the to junction at the end of the road, and made the hard right turn as i accelerated out, there is a knocking and vibration, the simptons are 1) when turning with even the lightest of throttle applied there is a knock which can be felt through the car, its worse when turning right, but still there when turning left 2) Seems to be fine in a straight line, obviously I have been driving it very gently since it happened, so if I was to give it a bit of beans in a straight line it might do it. What are your thoughts guys? I'm thinking either diff or diff mount? but it hasn't done mega miles and is only running 360bhp, so would you expect a diff to go? I've looked under the car and there is no oil anywhere. I have spoken to a garage next to work, they are letting me get it on a ramp at about 14:30, I'm hoping to find a broken mount any advice or help will be much appreciated Edited December 22, 2009 by Garfy (see edit history) Quote Link to comment Share on other sites More sharing options...
AndyT Posted December 22, 2009 Share Posted December 22, 2009 Have you had the rear suspension mount bolts checked mate? Sounds like when everything's under constant load, it's all good but when the weight changes the resulting forces may be causing something to shift. May be way off but I've read of it before. Quote Link to comment Share on other sites More sharing options...
Dnk Posted December 22, 2009 Share Posted December 22, 2009 A drive shaft possibly, as in the c/v joint has failed !! Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 A drive shaft possibly, as in the c/v joint has failed !! wouldn't that cause noise and vibration all the time though? seeing as the rear wheels aren't really changing angle Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 Have you had the rear suspension mount bolts checked mate? Sounds like when everything's under constant load, it's all good but when the weight changes the resulting forces may be causing something to shift. May be way off but I've read of it before. as in the rear subframe bolts? Quote Link to comment Share on other sites More sharing options...
Dnk Posted December 22, 2009 Share Posted December 22, 2009 (edited) wouldn't that cause noise and vibration all the time though? seeing as the rear wheels aren't really changing angle Yes i agree but just throwing ideas in the air, sometimes things dont always make sence on cars so i rule out the easy bits 1st Turning left or right shouldnt affect the internals of the diff so as suggested check all the mounting bolts and any other bolts on the back end 1st, Edited December 22, 2009 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 Yes i agree but just throwing ideas in the air, sometimes things dont always make sence on cars so i rule out the easy bits 1st good thinking Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 Turning left or right shouldnt affect the internals of the diff so as suggested check all the mounting bolts and any other bolts on the back end 1st, thats a good point actually, I guess all the internals are turning when drivning in a straight line, they just turn at different speeds when turning, but, hang on, are the planet gears turning when driving straight? Quote Link to comment Share on other sites More sharing options...
Dnk Posted December 22, 2009 Share Posted December 22, 2009 Check everything that you can if youve got a ramp to put it on, wheel bearings, dampers, are the wheel nuts all tight etc I checked a mates na a couple of weeks ago as he said he had a knocking noise turning left and turned out to be the wheel was loose on all 5 nuts !!! and didnt have spigot rings fitted !!! so was clonking around and due to fall off in the next few miles. Quote Link to comment Share on other sites More sharing options...
Dnk Posted December 22, 2009 Share Posted December 22, 2009 (edited) thats a good point actually, I guess all the internals are turning in a straight line, they just turn at different speeds when turning, but, hang on, are the planet gears turning when driving straight? Now you mention it im not sure so perhaps youve hit the nail on the head maybe, if you hold one wheel and spin the other it might give you an answer on the ramp with the wheels in the air, i'd have thought broken gears in the diff would sound awfull Edited December 22, 2009 by Dnk (see edit history) Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 Now you mention it im not sure so perhaps youve hit the nail on the head maybe, if you hold one wheel and spin the other it might give you an answer on the ramp with the wheels in the air, i'd have thought broken gears in the diff would sound awfull yeah true, I'll give that a go, thanks fella Quote Link to comment Share on other sites More sharing options...
Dnk Posted December 22, 2009 Share Posted December 22, 2009 If you suspect the diff then take the drain plug out and empty the diff oil into a clean container, pour it though a tea strainer and you'll sooon see if its broke a gear etc as there will be metal bits in the oil. Quote Link to comment Share on other sites More sharing options...
AndyT Posted December 22, 2009 Share Posted December 22, 2009 as in the rear subframe bolts? Yup, and everything's Dnk's mentioned. Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 If you suspect the diff then take the drain plug out and empty the diff oil into a clean container, pour it though a tea strainer and you'll sooon see if its broke a gear etc as there will be metal bits in the oil. its got to get me home tonight first, so I'll try that over the christmas break if I can't find anything else, good advice that Quote Link to comment Share on other sites More sharing options...
Dnk Posted December 22, 2009 Share Posted December 22, 2009 Best of luck with it and hope its a nice easy fix and not the diff Quote Link to comment Share on other sites More sharing options...
leelbuk Posted December 22, 2009 Share Posted December 22, 2009 Does sound diff related to me As you turn the car, one wheel will have to spin faster than the other which obviously is exactly what the diff is for, and thats when the issue occurs. My last car did the same thing although was FWD. Car was perfect in a straight line (I even drove the car 70 odd mile to the garage like it!), but as soon as I tried to put torque either way through the transmission while turning (i.e whether accelerating or engine breaking) I would get a loud clonk/bang. Turned out diff gear was shafted One way I proved it on mine was to lift the car in the air (with chocks around wheels on the ground) so both driving wheels are off the ground, then start the car and put it in gear. The wheels will spin and if you use something to lever between the floor and one of the wheels (I used a piece of thick mdf) it will slow the wheel down slightly to engage the diff and cause the banging/knocking. I'd check the diff oil first and simply try and spin one of the wheels whilst the rear end is off the ground to see if it behaves as it should Lucky for you it's RWD so not end of the world to get that changed if it is causing the issue. Good luck mate Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 yep, its the diff, its seized up, you can't turn the wheels with the car jacked up, and the knocking is the wheels slipping because the diff is now behaiving like a welded up diff, ho hum. Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 the question is, do I dare drive it the 25 mile journey home? Quote Link to comment Share on other sites More sharing options...
AndyT Posted December 22, 2009 Share Posted December 22, 2009 the question is, do I dare drive it the 25 mile journey home? I'd give Suprash a call and see if he can help. At least you found the problem and it hasn't taken long. Quote Link to comment Share on other sites More sharing options...
Guest Garfy Posted December 22, 2009 Share Posted December 22, 2009 my nan lives round the corner from work, so I've put it in her garage, and a friend of mine is coming to pick me up Luckily I have 3 cars so it can stay there till I get a diff Quote Link to comment Share on other sites More sharing options...
Ian C Posted December 22, 2009 Share Posted December 22, 2009 yep, its the diff, its seized up, you can't turn the wheels with the car jacked up, and the knocking is the wheels slipping because the diff is now behaiving like a welded up diff, ho hum. I hate to ask this but you did take the handbrake off after jacking the car up, didn't you? -Ian Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted December 22, 2009 Share Posted December 22, 2009 I hate to ask this but you did take the handbrake off after jacking the car up, didn't you? And took it out of park? Quote Link to comment Share on other sites More sharing options...
Ian C Posted December 22, 2009 Share Posted December 22, 2009 And took it out of park? Aha my man that'd still have some slack Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted December 22, 2009 Share Posted December 22, 2009 Are you sure it hasn't got an after market plate type LSD and it was getting a work out in the snow, and getting a bit grabby? The LSD in my Skyline makes it sound as if the whole diff assembly and subframe are going to come off the bodyshell when one wheel is on a very slippy surface. Has it ever made any odd noises from that area before? Do you abuse it by drag race starts? The CWP and differential are pretty bullet proof unless you drag race the car or it has a LOT of torque, assuming it's got oil in it.. Quote Link to comment Share on other sites More sharing options...
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