Still have the dreaded clunk! What's the deal?
04-08-2013, 03:45 PM
#22
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04-09-2013, 10:34 AM
#23
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Ok, I've noticed that if I'm coasting in neutral at 20-30 mph range and I clutch in and then shift freely between 3rd 4th continuously as I'm coasting, I can replicate some of the clunk that I'm experiencing. I do not experience this while the car is parked, only in motion.
Can anyone replicate or explain what is happening in this instance?
Good luck with that, the weather has been on some bi-polar nonsense. Snow showers on Friday?! Spring is here!
Can anyone replicate or explain what is happening in this instance?
Good luck with that, the weather has been on some bi-polar nonsense. Snow showers on Friday?! Spring is here!
04-16-2013, 12:35 PM
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04-16-2013, 01:41 PM
#27
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-----------------------------
Photos taken 2 years ago when I replaced the stock OEM bushing with the CS bushing and added the diff block and trans mount. I rented out their tool for the removal of the OEM bushing:
Last edited by KamaSutra; 05-07-2013 at 01:34 PM.
04-18-2013, 10:49 AM
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Yea, good point, I'm not cammed.....yet. Stock, the CS mounts have some vibration but nothing extreme. It's more noticeable now with a lightened flywheel and a grip happy clutch. If I clutch out slowly on take off, I can see the hood vibrate slightly.
I ordered a Revshift 95A differential bushing for now. If my CS bushing has failed, I'll know right away with the replacement Revshift. I'm going to have to go underneath the car anyway to check everything again and report back. I have to route a hose for the stock vent also.
In addition to researching for a new driveshaft, I also read that someone managed to break a differential bolt which would cause a clunk.
I ordered a Revshift 95A differential bushing for now. If my CS bushing has failed, I'll know right away with the replacement Revshift. I'm going to have to go underneath the car anyway to check everything again and report back. I have to route a hose for the stock vent also.
In addition to researching for a new driveshaft, I also read that someone managed to break a differential bolt which would cause a clunk.
Here is a video of my current CS diff bushing. As the video description says, car is stationary at idle, with my foot on the brake and partial clutch engagement this is what the diff is doing.
04-18-2013, 12:41 PM
#30
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Small world, I posted on your thread on there also.
I just got the bushing in the mail today. One step closer to seeing if I can get rid of the Getrag Shake!
I just got the bushing in the mail today. One step closer to seeing if I can get rid of the Getrag Shake!
04-18-2013, 12:46 PM
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So many people hate on the BMR pinion brace, (without proof) I ran the pinion brace with a UUC diff bushing and never had a problem with my IV gen diff, with the addition of anti wheel hop axles.
The last year I ran it, I also added the CS diff block. The thing was snug as a bug.
Mind you I still had some clunk, which was most likely due to diff backlash and the stock driveshaft bearing.
The last year I ran it, I also added the CS diff block. The thing was snug as a bug.
Mind you I still had some clunk, which was most likely due to diff backlash and the stock driveshaft bearing.
05-06-2013, 02:05 PM
#32
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OK, yesterday was Differential de Mayo for me.
I was able to get some shop time with my mechanic to diagnose the clunk I'm experiencing along with installing the new Revshift differential bushing and rerouting the differential vent.
I found out that my Creative Steel trans mount isn't looking too good, it's still there but I can feel the polyurethane deteriorating. If you look closely at the picture, you can see it's beginning to shift slightly off the mount.
There was some random grease that was scattered around the diff pinion seal and heat shield. Discovered that was coming from the driveshaft end. Looks like I'm going to need a driveshaft regardless...
We had the car on the lift and ran through the gears, I was able to replicate the clunk when downshifting without a rev-match. Nothing appeared to hit anywhere which is what it sounded like. We found the clunk noise was coming from inside the differential. Drained the fluid, some metal shavings on the magnet, nothing out of the norm though. Mechanic used a camera to see if we can find any chipped teeth or carnage inside but there was nothing visible outside the norm.
The differential had to come out completely because the old CS bushing still had to be pressed out. Last time I rented the CS tool that allowed us to keep the diff in the car. This time we improvised with a drill bit, air chisel, and an electric hacksaw for the sleeve.
We also took out the pinion gear just so we could get a better view at what the camera wasn't able to see. Nothing other than wear for the car's mileage. Do I have severe backlash? Probably, I honestly don't know what to think anymore, maybe I should accept the fact that it's German garbage and move on....
The car runs and the drivetrain clunk is subdued again but the internal diff clunk is still there. I had some light whine before, now it's more pronounced. Is the car better with the new Revshift diff bushing? Absolutely! Did it completely fix my problem? No, it appears that I have more problems than a new diff bushing would fix.
Suggestions are welcome (I already know a V2 would fix everything but it's too far out right now)
Anyone have experience with an internal noise in the differential like this?
I was able to get some shop time with my mechanic to diagnose the clunk I'm experiencing along with installing the new Revshift differential bushing and rerouting the differential vent.
I found out that my Creative Steel trans mount isn't looking too good, it's still there but I can feel the polyurethane deteriorating. If you look closely at the picture, you can see it's beginning to shift slightly off the mount.
There was some random grease that was scattered around the diff pinion seal and heat shield. Discovered that was coming from the driveshaft end. Looks like I'm going to need a driveshaft regardless...
We had the car on the lift and ran through the gears, I was able to replicate the clunk when downshifting without a rev-match. Nothing appeared to hit anywhere which is what it sounded like. We found the clunk noise was coming from inside the differential. Drained the fluid, some metal shavings on the magnet, nothing out of the norm though. Mechanic used a camera to see if we can find any chipped teeth or carnage inside but there was nothing visible outside the norm.
The differential had to come out completely because the old CS bushing still had to be pressed out. Last time I rented the CS tool that allowed us to keep the diff in the car. This time we improvised with a drill bit, air chisel, and an electric hacksaw for the sleeve.
We also took out the pinion gear just so we could get a better view at what the camera wasn't able to see. Nothing other than wear for the car's mileage. Do I have severe backlash? Probably, I honestly don't know what to think anymore, maybe I should accept the fact that it's German garbage and move on....
The car runs and the drivetrain clunk is subdued again but the internal diff clunk is still there. I had some light whine before, now it's more pronounced. Is the car better with the new Revshift diff bushing? Absolutely! Did it completely fix my problem? No, it appears that I have more problems than a new diff bushing would fix.
Suggestions are welcome (I already know a V2 would fix everything but it's too far out right now)
Anyone have experience with an internal noise in the differential like this?
10-21-2013, 10:54 AM
#33
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Some updates since I last posted.
My driveshaft started acting up 2-3 weeks ago, the center bearing started to chirp like a cricket off/on and
the rear clunk got even worse to the point where I could feel the windup and backlash transferring to the FRONT of the car. The CV joint has most likely ran out of grease.
Unfortunately not enough funds were allocated for a 9" swap so I have to make due with what I can since this is my daily driver.
I have a DSS aluminum one piece driveshaft on the way and I ended up ordering a new 4th Gen Differential from Luke at Lindsay Cadillac. I'll be reusing the Revshit differential bushing.
So this is it, there are no more excuses. Short of getting a 9" swap, this is about as good as it's going to get for me. All the stock **** is gone from the driveline minus the new differential. We'll see how this goes...
My driveshaft started acting up 2-3 weeks ago, the center bearing started to chirp like a cricket off/on and
the rear clunk got even worse to the point where I could feel the windup and backlash transferring to the FRONT of the car. The CV joint has most likely ran out of grease.
Unfortunately not enough funds were allocated for a 9" swap so I have to make due with what I can since this is my daily driver.
I have a DSS aluminum one piece driveshaft on the way and I ended up ordering a new 4th Gen Differential from Luke at Lindsay Cadillac. I'll be reusing the Revshit differential bushing.
So this is it, there are no more excuses. Short of getting a 9" swap, this is about as good as it's going to get for me. All the stock **** is gone from the driveline minus the new differential. We'll see how this goes...
10-21-2013, 01:49 PM
#35
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Not enough time to get it an 8.8 done the way I would have liked (Ironic I know). I need this car running within the next 2 weeks. I personally can't do that with a budget build 8.8.
11-11-2013, 11:55 AM
#38
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Following up,
So the new DSS 1 Piece Aluminum Driveshaft is installed along with a brand new 4th Gen Differential.
The initial impressions are some-what positive. I need to drive like a grandma for the break-in period so I can't comment on how it feels under real acceleration or a launch.
Is it better than before? Yes, there are less vibrations and acceleration is smoother. The car feels like it will squat hard under WOT. No differential whine even with the KARS III kit, 95A rear cradle bushings and the 95A differential bushing, there's still a howl that comes from the KARS III kit but that's "normal" for that setup.
Is the clunk gone? NO...this was the first thing I tested as soon as the car came off the lift. I accelerated lightly and then clutched in...CLUNK. I reversed lightly and then clutched in...CLUNK. Under normal driving it will clunk, but if you give it some more throttle and clutch out gently, its subdued. This clunk is all engagement and internal to the differential.
I remember reading threads where dealerships commented on the clunk with "That's just the way it is." I'm a believer now. This series of Getrag differentials are not engineered right at all. I bet I could have just changed my driveshaft and would have ended up with the same result on my old 4th gen diff. In other words, there was nothing wrong with my old 4th gen diff other than the typical whine that develops over time.
Thought about removing the KARS III kit and take it around the block just to see how it feels without it, although I doubt that removing the kit will ease the clunk. We'll see...pics and more info to follow.
So the new DSS 1 Piece Aluminum Driveshaft is installed along with a brand new 4th Gen Differential.
The initial impressions are some-what positive. I need to drive like a grandma for the break-in period so I can't comment on how it feels under real acceleration or a launch.
Is it better than before? Yes, there are less vibrations and acceleration is smoother. The car feels like it will squat hard under WOT. No differential whine even with the KARS III kit, 95A rear cradle bushings and the 95A differential bushing, there's still a howl that comes from the KARS III kit but that's "normal" for that setup.
Is the clunk gone? NO...this was the first thing I tested as soon as the car came off the lift. I accelerated lightly and then clutched in...CLUNK. I reversed lightly and then clutched in...CLUNK. Under normal driving it will clunk, but if you give it some more throttle and clutch out gently, its subdued. This clunk is all engagement and internal to the differential.
I remember reading threads where dealerships commented on the clunk with "That's just the way it is." I'm a believer now. This series of Getrag differentials are not engineered right at all. I bet I could have just changed my driveshaft and would have ended up with the same result on my old 4th gen diff. In other words, there was nothing wrong with my old 4th gen diff other than the typical whine that develops over time.
Thought about removing the KARS III kit and take it around the block just to see how it feels without it, although I doubt that removing the kit will ease the clunk. We'll see...pics and more info to follow.
11-15-2013, 10:19 AM
#39
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Here's are the pics of the install....
New 4th Gen Differential
New 4th Gen Stock Bushing removed
New DSS 1 Piece Aluminum Driveshaft (I have a PISNUOFF short throw shifter so I had to flip the nylon cup and shifter plate bushings for clearance)
Old 4th Gen getting removed
Old 4th Gen Revshift 95A Bushing removed
New 4th Gen and Old 4th Gen
New 4th Gen w/ Revshift 95A Bushing
New 4th Gen Diff installed
Without KARS III Kit
With KARS III Kit
The clunk will never go away...
New 4th Gen Differential
New 4th Gen Stock Bushing removed
New DSS 1 Piece Aluminum Driveshaft (I have a PISNUOFF short throw shifter so I had to flip the nylon cup and shifter plate bushings for clearance)
Old 4th Gen getting removed
Old 4th Gen Revshift 95A Bushing removed
New 4th Gen and Old 4th Gen
New 4th Gen w/ Revshift 95A Bushing
New 4th Gen Diff installed
Without KARS III Kit
With KARS III Kit
The clunk will never go away...
Where the hell are you souring an 8.8 kit for 2,000? The diff alone is around 1200$ Drive shaft 7-1300$ range and CV's 8-1200$ range. Not to mention the brackets, cover and all the other hardware needed?