Hi all,
I have a 2wd saph which has been on the road for a couple of months now, the problem is not always there so im finding it hard to trace. Basically I get a "clonking" sound sometimes when I pull away going forward and reverse, recently I have noticed that when dropping down a gear from 3rd to 2nd it also does it but not as loudly. The sound is very loud and only does it once. It sounds like metal hitting metal and I can feel the impact from it through the floor pan when driving. I have checked the bushes on the front and back end and all seem ok, the diff mount has some play in it but nothing major. I have now changed the gearbox mount for a vibra-technics one, I was expecting the car to vibrate a bit with it fitted but it vibrates a lot and the "clonking" noise has become more dominant.
Can anyone advise or suggest something i should check as other than replacing the diff mount i have run out of things to check.
Any advise would be much appreciated.

cheers

Gary

 

did you check your engine mounts mate?

 

Yeah checked them, they seem fine. I kept the handbrake on and started riding the clutch with someone looking under the bonnet and there was no excessive movement, when they were put on the car they were in good condition.

 

i would say diff mount or maybe backlash in the diff?

 

I think i will get a new diff mount from MSD and see what happens.
What is backlash in the diff? does this only happen if the diff is worn?

 

i think the poly diff mounts increase vibration and noise in the car.backlash is preset so there is only enough room between the gears for oil.if the gears are worn then the diff will clunk,could be the center prop bearing,that does wear out too.get under and get the rear wheels in the air and turn the prop and see if the prop turns a bit before turning the shafts,and grab the prop to see if there is any play.

 

It won't be backlash in the diff if hearing on changing gear etc, when selecting 1st or reverse yes it could do this.
Vibratechnics are shit for the road, should have used just a std one if needed but wasn't the cause anyway, have a look at the actual joints on the prop.
tabetha

 

Ive checked the prop joint and there is some play in the mount but nothing excessive, the rubber appears to be in ok condition too. I will be going back to the standard gearbox mount and will change the diff mount while its jacked up. I turned the prop and the wheels turn instntly, there does not appear to be any slack or play before the wheels turn.

Thanks for the advice chaps. lets hope the diff mount solves the problem.

 

have you checked the drive shafts ? just changed mine to low milage ones as had a simular problem.

 

Well today I took the car for a spin after nipping every bolt and nut on the underside up, and the "clonking" has disappeared, all i have now is vibration which is proberly from the gearbox mount. I have a diff mount on the way but cant decide to keep the vibra technics gerbox mount on or go back to standard. The uprated one makes the gear changes so nice, smoothe and precise. Im now wondering if the prop shaft rubber needs replacing and the prop balancing as it only vibrates badly at certain points in the rev range.

 

bit the bullet and have recently replaced all the mounts, GGR diff mount vib-tech fast road 2wd gearbox mount and Collins engine mounts from Motorsport Developments, and I have to say that it has totally transformed the way the car drives and as you mentioned the gear change is now sweet as a nut, many people have said that the gearbox mount transmits to much noise but in my opinion it hasn't made that much difference, and what you gain is well worth that little bit of extra noise.

"I am now in love with the car again"

Have you got uprated engine mounts? I was advised to change the standard engine mounts even though my engine mounts were nearly new, they are still to soft when used with a uprated gearbox mount.