catmandoob

Hi all, just a heads up I kinda just wanna stab my eyes out right now.

Ok, so I have had new engine mounts installed and Trans mount. I now have a kind of knocking and grinding sound right under my Trans tunnel from the sound of it. It does it stopped at idle in all gears. I can consistently get the sound by doing a tight left turn.

Have a lead maybe driveshaft carrier bearing. Has anyone heard a sound like this before and I know I know but I've looked and see nothing rubbing best I can from underneath, sound is all I have, you can't even hear it outside of the car.



EDIT: Future Reference, appears this is the sound of a bad flex plate, will get inspected and update to confirm.

crehop

https://mbworld.org/forums/c63-amg-w...-knocking.html to me these sound the sameish.

catmandoob

Good lead, does oddly sound close but mine is more from directly under the gear shift and ashtray area. Thinking torque convertor maybe, I do have TCU tune so maybe I'll do a trans service and see if that helps.

blay127

i just had a similar noise on mine after doing engine and trans mounts. it would only happen when turning left with some throttle. For me it was the exhaust pipe on the drivers side contacting the trans crossmember. Get underneath and follow the exhaust and see if its close to the body or anything else solid. Mine had a 1/8" gap sitting still but would obviously contact when driving. I took the crossmember down and ground away the edge to make clearance since there was no good way to adjust the exhaust.

Lewisracing97

Mine is doing something similar. Was underneath changing the exhaust and didnt see/feel anything loose or rubbing. Hopefully not trans related. Had the motor mounts done a few months ago as well. Will continue to look into it and see if maybe the sound continues with this new exhaust, maybe it was rubbing.

catmandoob

If it's really close to the sound and it comes from right under and in front of the shifter area check your flexplate,driveplate, ring gear, flywheel whichever term you want to use. Mine is going in next week and I'm pretty sure it's a cracked flexplate causing this sound for me.

catmandoob

Just thought I'd give an update. Local dealer has car now and is confident it's not my flex plate/drive plate. They were able to replicate the sound but apparently it has them all confused and off as well. Phil started to say they noticed the engine mounts and trans mount but my rebuttal to that was yes it may have slight increased vibrations but that's not what could cause a knock under trans tunnel area. Nothing is loose so no exhaust rattle or connector some how tapping.

This is a sure odd scenario, all I did was have engine and trans mount replaced. I pretty much sucked it up and asked Phil to go until they know, really hoping teardown doesn't get too involved.

But for anyone still curious what happened in this situation. Had a shop replace engine mounts, first start and had instant trans tunnel knock sound right under shifter area. From sound I gravitated to cracked flex plate. Had shop kind of check and without confidence they agreed possible as they couldn't see anything else. Now Benz has had it for 2 days which Phill has been great in trying to redeem from my last horrible experience there, but they have no answers at all.

Good news is I'm finally doing the Takata airbag recall that thankfully hasn't killed me yet.

Edit: well interesting twist. Dealer is saying its my rack and pinion causing this sound. I feel a bit odd about that because all power steering is in the front as far as I can tell so not sure how that translates to knocking from bell housing and adjusting with rpm not even touching the steering wheel.

I went ahead with the replacement but I feel like I might be getting fleeced and I'm still going to have that issue in my vid.

My question is, had anyone experienced a rack and pinion causing a similar sound? 3k to fix which i went a head and rolled with. Just not sure how the other shop agreed it was flex plate now.

All I can assume is I didn't get my new filter and res. For power steering in time and it ate itself up. They did say power steering pump was good still though.

Any thoughts?

catmandoob

Update, dealer says its rack and pinion causing noise.

Thoughts from the community?

catmandoob

Sorry to bump this again but maybe someone else will find this useful in future reference.

So got the car back today, upon first start at dealer it was a good normal start. I paid and hoped for the best. Knowing it was only when starting I knew it would take a day or two maybe. Instead as soon as I got to house and parked it for 10 minutes and went back out to start it, bam there it was.
I'm having a hard time getting anyone to understand what I need inspected. Reading the bill of sale the service guy Phil relayed to the technician that Client states drive shaft housing is cracked. How in the lords good name does inspect for a cracked flex plate/drive plate turn into that description?

I'm dumbfounded on the lack of competence at these dealerships and in the end while my spool valve was skipping apparently in the power steering rack, I'm sure a flush and my new res. and filter would have lasted and worked just fine.
So now I'm stuck on still thinking it's a cracked flex plate..... no I haven't be able to crawl underneath to check myself but I shall this weekend if I can hopefully, maybe I can figure out a way to inspect through inspection port like I would have thought the dealership would have done. If only I had a dang lift.

Does anyone have a way I can describe a flex plate better to people so they can comprehend what the hell it is?

I have looked for loose objects and such but I see nothing the new engine mounts would have adjusted their placement enough to ting or clank against anything. I'll do another video in the morning on way to work of the sound and see if I can get it better.

duuder

damn, thats pretty ****ed up they havent been able to figure that out yet. i had my flex disc crack recently and it was pretty clear (via facetime) when it was on a lift. w/o being underneath, i thought it was a world of issues ie shaft, bearings, mounts... total cost at my indy was 700 bucks (2.5 hr labor, flex disc, and a small weld in my exhaust) and it was for a black series

catmandoob

Ok finally have car back and its been 4 days and smooth sailing. I kick myself because I was on a witch hunt but it sure enough ended up being something simple and easy. I have to give a shout out to Phil and the men as well. Apparently from where the exhaust had sagged from engine mounts dropping enough and height of ECE engine mounts the new mounts adjusted alignement just enough that depending on angle car sat it was rubbing the trans support brace just enough. So after 2 weeks of their techs going over every inch pretty much they honed in on it and just took a couple washers and some longer bolts to adjust.

Whew, I almost went down a crazy path and even had 2 other garages agree with me which kind of helped me go down the rabbit hole. In the end I'm happy because I had to replace rack and pinion eventually probably and I did change res for PS as well to eliminate whine and future damage to rack.

I guess lesson learned and as blay127 mentioned with new engine mounts it can adjust geometry because of how awful OEM engine mounts are for sagging and misaligning everything. MB said it was just barely touching at times but from where I have upgraded stiffeners at trans tunnel area it just rattled whole body.

Thank You blay127, what I did was start consistently driving until I could replicate it and then I had one of MB's techs ride with me. From there they put about 200 miles on it in between their road tests and lift inspections. The turning wheel full left lock and replicating it was key.

Appreciate all the MBWorld Fam and help, hopefully this will help others feel more comfortable always double checking exhaust contact points when we here things like this now.

And thank you Creative steel for making great engine and trans mounts, they double checked all proper alignment specs especially on trans mount and was spot on to what MB calls for. The tech even said they hate the mounts MB uses because when people don't keep up with them it misaligns so many things sometimes and we chalked it up to the combination of OEM mounts sagging when I had headers installed and then the ECE mounts probably were just right to not notice it with them especially since they kind of sagged so quick.

I also want to mention that Phil and his techs were kind enough to not even charge me since it took so long and he comped all their time on it this time around. So case closed and it feels so good to drive it again.

Creative Steel

Awesome to hear that you got this noise sorted out. Intermittent problems are the worst!

blay127

glad yall finally got it handled. was fairly confident you were describing the same issue i was having after a similar situation. (LTH installed with collapsed engine mounts, then install new engine mounts.) Sucks about the steering rack but hey, now you have peace of mind knowing thats a major component with 0 miles. Hope you get to enjoy the car worry free now

deadlyvt

Glad creative steel has another option for us in this department. I have the ece mounts still doing fine but if they melt like others I'll look into them. Hopefully they hold up 👍