Lude Generation

I'm experiencing the most annoying clunk from the front end every time i sharply apply throttle or cut it off. I kind of narrowed it down to the driveshafts / perhaps gearbox.

When the car is standing still, I apply all the brakes and apply throttle to the wheels, and the clunk is not heard.
If I only apply the handbrake and apply throttle to the wheels, the clunk can be heard!
Apparently when i dont apply the front brakes, the wheels turn ever so slightly to make that goddamn clunk.

So yesterday I went under the car to wiggle the driveshafts a bit and the only apparent play I found was in the gearbox / diff itself ->
(I removed the wheels for this "test", so the driveshafts could spin freely)


Is this normal?

The clunk is most noticeable and awful when coasting in first gear and sharply cutting off and applying throttle

I've had this in both my ludes and posted about it a few times.

you can clearly see from your vid that the shaft and the CV joint are moving in unison (double handed you can confirm there is no play there), and even though you cant tell in the video, its definitely coming from directly inside the gearbox, right inside the diff housing section. the fact the inner CV isnt moving reules out diff carrier bearings.

i think it is just internal wear to the diff planetray gears, and not much you can do about it.

My old 5th gen did this not long after I bought it. My current lude also does it. Ive had the gearbox out, new diff bearings / shims / input bearings / 2nd hand ATR diff slapped in, its slightly better, but its still there...

I suspect the diff planetary gears just get worn out, and that's what you get as a result. It does make slow speed driving annoying for sure - I put up with it for many years in the old lude. It scarcely got worse over many years, and that included track days - so you will just have to put up with it, or get ready to change the box when your clutch next needs doing.

changing the gearbox oil does nothing (as i had changed mine several times on both cars prior to track days).

infact, i still have the old diff in the garage, ill go and check it now actually (forgot rich at PAW gave me all my old bits back).

Confirmed, but slightly different to what i expected.

so the issue is not the crown wheel (either play in the teeth or slack where it is mounted to the diff unit), or even in the planetary gear teeth as expected. Its not in the central bar either.

The issue is the way the 2 CV receivers are carried in the diff unit itself. There is slack where the inner CV splined part is. I have about 1mm play in both parts. I took a video and will try to upload it as it shows it much better than i can explain.

My diff still had the inner race of the roller bearing on , so not sure what it underneath, and whether there are hidden bearing that could be replaced to resolve the issue. I also think you would need to take the center shaft out to allow the inner CV carriers/gears to come out...

Video incoming when i can work out how to get it off my phone and onto the webs.

Wow, you really did your homework on this one.

So with the play you experienced, did you also have this annoying clunk when tapping/quickly applying the throttle? It's driving me crazy.
If I coast at 1st gear idle, and the car is jumping/rocking it sounds like my engine will come apart

Whenever the car rolled onto, or off of power, it would clonk. EG, slow driving in 1st gear (car park, stop/start traffic).

I got under the car, both front wheels off the ground. On my back, arms out wide, roll either wheel forward/backwards, and i got the clonk inside the gearbox exactly as you posted. No slack in the inner CVs (like yours) and no slack in the intermidiate bearing or outer CVs (you can check by holding each piece with a seperate hand)

Video is bluetoothing over now from my phone - will find a way to send it...

I just checked the prelude manual, the diff carrier is only mentioned to inspect for cracks - so there is no serviceable parts according to the manual. I'll see if i can remove the outer taper bearing tomorrow, and then have a crack at removing the central shaft, then see whats holding the outer planetary gears inplace, because that is where the slack is. I expect this might be destructive dismantling as that central shaft looks pressed in / deformed into place.

sorry for the shaky camera work and the absolute tip that is my garage.

http://www.scottwoodcock.co.uk/diff.mp4

Wow, thanks for the extensive effort
But one thing that I noticed in your video, there isn't any rotational play when you rotate the gears at ~0:19
Whereas in my video, there is rotational play, and no play in the up-down-left-right directions (the teeth on the inner CV joint mate perfectly with the gearbox's teeth).
So I'm not quite sure if we're on the same page here.

It might be that my play comes from somewhere deeper/further inside in the gearbox?

Do you by any chance have a fully built gearbox to check if it has this kind of play that I'm experiencing?

I'm gonna head out to the local junkyard, I know the guy has a prelude tranny and I'm gonna check the play with an old inner CV joint I have lying around (it got replaced by the one shown on the video)

I know it seems counter intuitive, but its the same noise i had in the same manner you posted.

I guess it makes sense. Even if the inner CV keeps the gear central (as the CV shaft sits in the the outermost part of the diff casting), the gear is still free to ride up and down the end of the CV spline (there it nothing to keep it from moving up and down?)

Since the gears are angled, there is a thrust moment on that planetary gear, and this is what you hear, its riding up and down the end of the CV shaft, and smacking into the differential casting, that that's the slack/noise.

Last lude did it, and this lude did it, and this is the diff from that lude. Exactly as your video.

I dont have any CV joins to show, but i suspect with CVs in place both sides, i would have the same slack as you. Perhaps tomorrow i will fish something out the garage to wedge into those gears to demonstrate that the rotation causes the same noise.

my box has been rebuilt partially, but i don't fancy removing my driveshafts, i still have the clonk to some degree...

Will try and do some more experimenting tomorrow.

Rear mount