I have a real puzzler on my hands here and can't quite figure it out. Vehicle details below and some story to my situation.

14 C63 507 Edition, 145k KM's mainly highway driving, religiously maintained. Stock tune, vehicle is spritely driven but not until all temperatures are optimal

On Tuesday, May 24th the vehicle was driven by my wife who said it was idling rough at stop lights, I drove the vehicle to work the next morning Wednesday, May 25th to see if I could feel anything. Vehicle felt like it was shifting pretty rough between 1-2 and 2-3. Merging on the highway under WOT from 3-4 and 4-5 and 5-6 and cruising between the high gears felt fine. I did some light reading on rough idle and some jerking during shifts during the day and decided to reset my TCU before I left work for the evening and see how it felt on the way home under the impression that when I drove it spirited on Monday and then my wife took it and drove it like a granny to school with the kids it didn't like that. It got progressively worse on the way home, car would shift from 2-3 at 2k RPM and felt like it was forcing a shift, dropped her into M mode to see if it was different under user control which did not help. When downshifting from 4-3 instead of going up to 3k-4k+ RPM it would immediately drop to 2k.

I limped her home the next 5km as I felt it being in my driveway would be better then the side of the road. Called my SA who said he'll have it towed to MB on Wednesday, June 1st.

In the meantime I decided to go take her for a loop around the block with my wife and asked her if it was doing this during her ride with the kids to school, of jolting and jumping when shifting gears, she said absolutely not. We were then sitting idle outside of our house in "D" on S+ mode and the idle got extremely rough and then a rough sound and she died, all lights on the dash. Turned it off and back on and it started no problem and sat in "P" without issue, popped it into "R" to back into the driveway and did the exact same thing again. Off and On and put it in "N" and it's fine, left it in "P" its fine, revved it up in both "P" and "N" and revved without issue.

There is no CEL, no issues or signs leading up to this happening, vehicle was running like a horse the day before. Threw it on a Carsoft scanner several times throughout this whole ordeal and got no codes whatsoever. Even after dying or during death there is no codes being thrown that's being picked up by my cheap scanner. Vehicle just had a service "A" completed about 1,000 KM's beforehand.

Has anyone had this happen to them before? Any idea's here? Is my best course of action just leave it with MB and let them diagnose? SA said it would be tough to diagnose without any codes but we haven't put it on a STAR scanner yet.

Video of it happening is attached

 

God, that sound is terrible.

 

Yeah doesn't sound good obviously

 

Isn’t that what a forum is for? To share opinions? I couldn’t find anything on the issue and decided to ask the community.

Would hate to pay to rebuild or replace an entire transmission if it’s something small like a sensor.

 

Yeah wow I would stop doing that. Get it towed. I would have said a sensor, but the grinding noise sounds like a bearing or you snapped something inside the transmission like the shaft that picks up the right gear. Just a totally wild guess not a diagnosis - sounds expensive sorry. Let us know how it works out.

 

Almost sounds like its something in the transmission. Problems seem to only appear when the trans receives any load. Pull some live data or take it to a experienced shop.

 

Yea, the noise is almost ear piercing, it’s getting towed to MB Wednesday for some professionals to look at it

 

Yeah, sadly. The noise is what makes me
think it’s pretty bad, only seems to do it under load and it happens no matter what. Getting towed to MB on Wednesday so hopefully will have a proper diagnoses soon.

 

Will be interesting to see what the issue is. Like blkrkt I am guessing one of the shafts have broken within the transmission and I'm 39% sure that's what your problem is!
definitely post up what they find for us

 

Yikes... Sorry man. Hope it isn't too terrible.

 

Got an update for this one, had the car towed to MB last week and they diagnosed, they found internal fault in the transmission and asked if they could proceed with removing transmission pan and inspect internal parts.

After inspection of internal parts they found several damaged components including Torque converter, large broken clutch material deposits. They want to replace the complete transmission assembly with quoted price of 12k CAD + taxes.

 

Ouch. Shop around for prices. Find a good indy shop and I bet the price will be lower.

 

Sorry for your luck. I agree with an Indy shop.

 

I spoke to a transmission shop recommended by a friend who said he would be able to rebuild for around 6.5k I still have sone shopping around to do and some clarification with MB on what they’re replacing exactly. I’m on the fence about letting MB do the work vs an Indy.

 

You could have them just remove the transmission and then have it built elsewhere and then put back in if you're worried about local ability.

I believe there are a few people on this forum who've had their transmissions rebuilt since superchargers tend to push the transmissions to the limit.

The cost situation won't be any better I imagine but at least you're not left with a gambling feeling.

 

I would advise not having a local guy rebuild your transmission unless they are absolute 722.9 specialists. They’re complicated. You’re better off shipping it to Weistec or Southern Hotrod if you want it built up for power and durability.