Clunking

[Budgie]

Hi,I have a slight clunking noise on my 81 c3 when going from park into gear,, could it be the u joints or gearbox mountings etc,runs fine once in gear, thanks

 

[Emc]

Our first port of call would be to check the diff front cushions

 

[Budgie]

Thanks,can you explain what the diff front cushions are,,

 

[antijam]

See here

 

[Budgie]

Thanks,,will get it seen to asap,,will it be safe to drive it without damage till repaired

 

[antijam]

As Emc suggests, this is just the first thing to get checked since it's a fairly common problem on C3's and particularly noticeable in auto cars.. As you have realised there are several other possible sources of a clunk but since the drive is OK once in motion it shouldn't be something needing immediate attention.

 

[Budgie]

Thanks,yeh,,goes through the gears,kickdown ok with no noise, clunking etc,,so will check it out when weather permits

 

[Alben78]

Strangely for a fairly common problem the internet seems very light on a “how to” for this.

 

[Budgie]

I agree,,

 

[Emc]

Simple job , if it is the cushions gone bad
Disconnect the driveshaft at the diff this will give clearance to remove the bolt
Undo the fixing bolt a wrench will be needed to hold the bolt
Remove upwards
Fit new upper cushion
Refit the bolt
Fit the lower cushion and torque up
Refit the driveshaft

 

[Budgie]

Done more research on this,,could it be the anti clunk spring in the th350 gearbox that could be the problem too,,,hope not,,,

 

[langlj00]

I assume the 'clunk' is whilst the car is stationary.
Could be a number of things:
Most likely the rubber cushion at the front of the Diff. but mine was good and eventually solved when I replaced the driveshaft U-Joints.
Does it happen going into forward and reverse gears?
If it happens as you pull away, it could just be the brake pads moving, the original calipers allow a little slop that can produce noise when going from forward to reverse (or vice versa).

 

[Budgie]

It only happens putting it in reverse or drive from stationery,,once moving no issues

 

[teamzr1]

How about jacking the ass end up and blocking the front wheels
Have someone put tranny and out of gears and someone at ass end see if they can focus in where the knock is coming from ?

 

[Budgie]

Yeh good point,can only assume like other users have said more than likely front diff bushes or drive shaft / half shafts u joints

 

[Forrest Gump]

How about jacking the ass end up and blocking the front wheels
Have someone put tranny and out of gears and someone at ass end see if they can focus in where the knock is coming from ?

I would be wary of doing that. With the wheels off the ground the half shafts will be drooping at an angle that the UJ’s are not happy working at which could result in damaging them.
Perhaps keep the car on the ground and use an inspection mirror to check the diff snub.

 

[Budgie]

Already thought of that,,will prob take it to a mates indipendtant Jag/landrover garage in Sheffield who has a lift,I'm hoping it's just the front diff bushes

 

[Alben78]

From memory, and it was some time ago, if it's the drive shaft joints once the rear is in the air it's pretty obvious where the problem is if you rotate the wheels by hand. They seem to show a rusty residue on the spiders as well.

 

[teamzr1]

I would be wary of doing that. With the wheels off the ground the half shafts will be drooping at an angle that the UJ’s are not happy working at which could result in damaging them.
Perhaps keep the car on the ground and use an inspection mirror to check the diff snub.

Do not tell anyone but I have done this several times for testing, had my 1999 C5 up to 140 MPH in my driveway

Those living near me bitched, I told them to wear earplugs !

 

[Budgie]

If it's the u joints on the half shafts or drive shaft would it not clunk each time you pulled away from stationery?,it only happens when putting into reverse or drive from stationery