29 replies to this topic

[lildeucecoop72]

Hi I am wondering if anyone has been in the same boat as me here, or perhaps a guru will know what it is? :)

 

I only noticed the problem as I was pushing the car in the garage.

As I push the car forward, there is a 'clacking' sound. This also happens when pushing the car backwards, but not as often. I suspect it's the gears or diff but can't understand what it might be...

 

Link to video of clacking sound whilst rolling the car in neutral.

I put the camera in engine bay, and you can see the camera jerk with the drive shaft on the first 'clack'. 

 

 

https://youtu.be/_Oy29Yf5vII

 

 

I then jacked the car up and spun the wheels by hand with these results:

 

-Neutral: Right and Left front wheels moving forwards  - 'clacking' sound.  Around 4-5 'clacks' per rev of wheel coming from diff or gearbox area.

-Neutral: Right and Left front wheels moving backwards -  'clacking' sound, though half as many times coming from diff or gearbox area.

-Gears 1-4: Right and Left front wheels no 'clacking' sound at all!

 

I did not test this with reverse gear, but can if need be.

I did not test test both wheels simutaneously moving forwards in 1,2,3,4 or R, but again, I can do this if this it it leads to solving the problem.

 

On the ground: 

-Neutral: Right and Left front wheels moving forwards together  - 'clacking' sound.  Around 4-5 'clacks' per rev of wheel coming from diff or gearbox area as seen in video.

-Neutral: Right and Left front wheels moving backwards together  - 'clacking' sound.  Around 4-5 'clacks' per rev of wheel coming from diff or gearbox area.

 

 

I am pretty certain its not the wheel bearings, CV or Hardy Spicers. These are OK or new and torqued to the required settings etc, and it would come from the guilty side of the car if they were the culprit. The sound is coming from the middle of the car.

 

I but in a new gear box/diff way back in 2009 (after losing the previous box due to transfergear failure (some bright spark had set the wrong endfloat before I owned the car).
This box/diff setup has been trouble free and driven about 5000 miles since then.

 

The engine and gearbox was recently out of the car as one unit while I tidied up other things. I did not tamper with the box or diff or clutch.
The only thing I replaced was one of the linkage arms. It's a remote type box, and standard diff if I remember correctly.

I also changed the oil and the level is correct.

 

I am really scratching my head and I am not sure if the car is OK to drive, so I am not driving it until I know more.

 

Thank in advance.

 

 

[Spider]

Could have broken a tooth of the Final Drive Pinion.

I'd suggest unbolting the Unijoints from the Gearbox and checking directly from the Flanges just to be sure it's internal. If it is, then no point guessing any further, it has to all come out regardless.

If you find the Pinion (and / or Crownwheel) has damaged / broken / stripped teeth then I would also suggest as a minimum removing the Mainshaft Bearing Retainer and check the Case for Cracks.
 

[lildeucecoop72]

Hi and thanks for quick response Spider, and good advice. 

Perhaps a silly question from me - if it's the final drive pinion/stripped teeth, why does it not make the clacking noise whilst in gear?

 

Could have broken a tooth of the Final Drive Pinion.

I'd suggest unbolting the Unijoints from the Gearbox and checking directly from the Flanges just to be sure it's internal. If it is, then no point guessing any further, it has to all come out regardless.

If you find the Pinion (and / or Crownwheel) has damaged / broken / stripped teeth then I would also suggest as a minimum removing the Mainshaft Bearing Retainer and check the Case for Cracks.
 

Edited by lildeucecoop72, 04 October 2022 - 05:41 PM.

[absx2]

Sounds a daft but I came across a noise like you describe and it turned out to be nothing more than the brake pads knocking on the caliper on one side from a very slightly warped disc not noticeable on the road.  It made a hell of a noise.

 

As Spider said, pop the shafts off to make sure it`s internal or hopefully something else.

[nicklouse]

Looking at that video the noise is not rotational with the drive shaft and does not seem to be regular.

 

I would rule out crown wheel to cv joint as they would be related. But there is an obvious jump when one of the nuts goes past. 
 

I would be pulling it out.

[Lplus]

That sort of sounded like horizontal play in the hardy spicer joints.  Dropping from one side of the joint to the other as the joint turns.

[lildeucecoop72]

Hi,  OK so here comes an update on this after I have removed both driveshafts and turn the flanges that are attached to the diff by hand.

Again, this only happens in neutral. The same occurs whether I turn/rotate in either direction.

 

If I hold one side and turn the other: Clack
If I turn both in the same direction: Clack

If I turn one side at a time: No clack

 

Video taken from under the car, here: https://youtu.be/M5k9BVWUQ9Y

 

 

Any ideas as to what it can be?
Thanks!

[Mr Piggy]

You'll only be turning the pinion when its in neutral. In gear you'd have to be turning the engine over aswell. When it's in gear you are just turning the diff gears, that's why they rotate in opposite directions. It could still be a diff bearing. That would probably give an irregular clunk where a pinion tooth would be regular.

[super6al]

Could it be the spacer/nut (thrust block is its Sunday name) on the diff pin sliding back & forth. Mine was quite loose before I replaced the fibre & bronze(?) washers

Alan

Edited by super6al, 15 November 2022 - 07:25 PM.

[lildeucecoop72]

You'll only be turning the pinion when its in neutral. In gear you'd have to be turning the engine over aswell. When it's in gear you are just turning the diff gears, that's why they rotate in opposite directions. It could still be a diff bearing. That would probably give an irregular clunk where a pinion tooth would be regular.

The clunk is regular on turning, when holding one side or turning both the same direction, but only in neutral- that’s what I don’t get.

[Mr Piggy]

Yes, you'll only be turning the pinion when it's in neutral. Unless you get someone to depress the clutch pedal. Then You'd be turning all the gearbox internals all the way up to the clutch centre plate.

[Mr Piggy]

Or are you saying that you can turn the drive flanges in the same direction even when it is in gear?

[Lplus]

 

You'll only be turning the pinion when its in neutral. In gear you'd have to be turning the engine over aswell. When it's in gear you are just turning the diff gears, that's why they rotate in opposite directions. It could still be a diff bearing. That would probably give an irregular clunk where a pinion tooth would be regular.

The clunk is regular on turning, when holding one side or turning both the same direction, but only in neutral- that’s what I don’t get.

 

So when it is in gear you can only rotate one side by allowing the other side to rotate in the opposite direction and there's no clunk?  Assuming so it seems the noise is only present when the crownwheel is turning the output pinion and the gearbox output shaft.  The internal diff gears don't seem to be the problem.

 

It seems the noise is centred on the interface between the crownwheel and pinion or in the output bearing, There's also the needle rollers between the 1/2 and 2/4 output shaft gears and the main output shaft and the input/output shaft needle roller, but I wouldn't expect those to make that sort of clunk.

 

For my £5 I'll go for a damaged crownwheel or pinion gear, though I suppose the reverse idler may be misplaced and catching on the 1/2 output shaft gear in one spot?

[Mr Piggy]

If the pinion nut comes undone the car will only drive in reverse. Doing this for a long distance can heat up the gear and the bush can move so the rev idler won't go back fully. I think that makes it difficult or impossible to select 3/4th gear then.
I think you're going to have to get in there to investigate but it does sound terminal for your cwp.

[lildeucecoop72]

Thanks for your replies.

I have since removed the box, but still haven't found the cause of the problem.

The pinion is tight, but the sound remains when turning both drive flanges. All the gears look OK, no damage or wear.
I don't think it's the diff, this seems OK, again no damage or wear.
The sound seems to be coming from the box itself, and there seems to be play.

I was wrong abut it not happening in gear. It does in every gear with the box on the bench, including reverse.
I guess I was not able to turn both wheels in the same direction whilst in gear, and the sound could not be heard over the engine when driving.

I have uploaded 3 videos for your primetime Saturday night viewing pleasure:

https://www.youtube....rts/FD-_txriMWk

Edited by lildeucecoop72, 10 December 2022 - 11:04 PM.