Parade Clunk Contributors

[rand49er]

Okay, everybody knows about the parade clunk,
but with a UUC flywheel on its way to me, what
I was wondering about is where is the primary
source or is there one single greatest contributor?

If I replace the stock flywheel with the UUC unit,
how much reduction in the clunk will that result in?
What about the driveshaft itself, or the various
rubber bushings throughout the drivetrain including
the motor mounts?

Furthermore, would getting rid of all that, for lack
of a better word, "slop" be desireable, or would
that result in causing too much shock to occur to
the whole drivetrain, especially the differential,
thus not be advisable? In other words, is that
"slop" built in to protect the drivetrain?

[CadiBlk]

I think this is a quest that many have taken and many have failed (or found that their wallets couldn't support it). But I wish you luck as I am sure there are many folks out here (me, me) that would love for you to be the one who found the fix. Search on!

[Twitch]

Motor mounts add to the clunk big time. After doing my diff bushing and MMs, my car is pretty much clunk free.
If your doing all that work, its only a little more to do the UUC mounts.

BTW I asked this question, and someone said the lighter flywheel makes the clunk worse.

[rand49er]

Motor mounts add to the clunk big time. After doing my diff bushing and MMs, my car is pretty much clunk free.
If your doing all that work, its only a little more to do the UUC mounts.

I was thinking the same thing.

I won't do the UUC flywheel till next spring/summer,
but those MMs might be a good idea at that time.

Tony, did you do the diff bushing yourself?

[Twitch]

Tony, did you do the diff bushing yourself?

No, warranty. That's something I would pay the dealer to get it done.

[trukk]

When I put in the UUC motor mounts it got rid of a LOT of clunk. Over the past 6 months some of it has come back, as the other bits have worn. I think as we stiffen up certain areas the other areas mya wear faster.

I'm still on a mission to de-clunk my car though. Next step will be the rear diff bushing prototype. After that, I will eventually can the dual mass flywheel, once my clutch goes. I'm currently at 80k miles, moded nearly the entire time to one extent or another, and the clutch is still going strong!

-Chris

[rand49er]

What is your take on the driveshaft contributing to this?

I agree with you, Chris, that as the various contributing parts are
eliminated with rigid or less compliant pieces that the remaining ones
wear out at an increasing rate. And, as we tighten this whole thing up,
it would seem to me that the diff is going to feel the shocks to the system
to a greater degree and could suffer as a result. Could it be that GM put
all this slop in there to not only give what they perceived as their older
Cadillac customers a smoother driving experience AND to protect what
they knew to be a suspect diff?

[nmaier2201]

I heard from a UUC thread that the Motor mounts were part of the clunk problem, but the main reason was the front bushing on the diff (there are two rears as well which are not a problem) that front one wears out and increases the clunk. Now I think that fixing the clunk is better for the drivetrain as it reduces deflection in the rear diff.... so if you can talk the dealer into swapping then front bushing on your diff out... I would do it. Like a couple others have said as well, replacing the motor mounts isn't a bad idea either.... it can't hurt any, see if you got any cracks on those motor mounts which might give you an idea of the condition they are in.

[The Tony Show]

I noticed a reduction in clunking when I added my Z06 flywheel. The funny thing about the clunk is that it seems to go away for a while any time you take something apart and put it back together, such as the rear cradle or motor mounts. Every time I've had the diff replaced I'm "clunk free" for a few weeks due to everything being torqued down properly, but then it comes back as all the bushings settle in and the bolts slightly loosen.

[Lindsay Cadillac Parts]

I should have poly diff bushing prototypes in a week or 2. hopefully if all goes well stock by the end of Nov/early Dec.

[nmaier2201]

Thanks Luke. I thought of you when I saw the MM and trans mount on UUC's website but no rear diff bushing... I know I heard they had one in the works.... Any idea on the steps to swap it out? you don't have to torch the old one out do you ?

[NormV]

It's the diff. What weight fluid is everyone running. I run Royal Purple 75w140 and it takes up most the slack between the pinion and output during transition. The lighter weight just amplifies it.

Now it is just an repeatable thud.

You should be able to tell which end of the car by turning your head(no coughing) or putting someone in the back seat.

Norm

[rand49er]

So, no one thinks there's a problem with trying to reduce contributions
to the clunk, and no one apparently thinks the driveshaft is part of it.
Interesting ...

Luke, would you be able to put together a complete bushing kit in the
future? Yeah, I thought you could. Seriously, though, the kit
might include UUC MMs, the tranny mount, and those new diff mounts.

Norm, you really think the fluid type/weight is an issue here?

[Junior1]

OK here's my take on this one...My V although it is an 05 has just broken 4,000 miles. There has always been a noticable clunk/thud while shifting 1-2 going slow...
just recently, the day after VDay II, I went to Lindsay and replaced the MM's with UUC's as well as the tranny mount. There was nothing wrong with the originals. I also replaced the shifter with UUC's and bushings as well.
What I do notice is that the considerable engine shake at shut-down has almost disappeared. You can feel it but very minimal and its gone very quick. It does feel more connected/rigid now.
The clunk however has gotten louder, and I'm attributing that to the add ons, including the shifter. Since everything is more solid its going to transmit more of the sound. I can even hear the tranny spinning in neutral now...I did find something out though, I noticed when I'm making my 1-2 shift or even 2-3 shift, if my RPM's are at or above 3,000 the noise is pretty much gone.

That leads me to believe that while maybe some of these parts were not originally designed/engineered to absorb the excess torque, more likely they were designed soft to keep a cadillac ride, they actually helped the drivetrain from taking additional punishment. I also think the driveshaft design serves the same purpose and I would guess some if not most of the clunk has to do with that area and the brace underneath it...but wtf do I know

[Den_93]

Randy, replace your rear diff bushing by adding a BMR rear pinion diff brkt. You can get one for $144 shipped and its easy to install. Thats what I did and it fixed the rear clunking. I need to get the MM/Trans mount kit to fix my front clunking noise to be clunk free.