[JPinSTL]

2018 RS Hatch 6MT Diesel approaching 30K. I seem to have developed a "clunk" in 1-2. I can feel it in the shifter and the floorboard with the clutch depressed. I hear it over the AC and with the windows up. When approaching a stop light and you were in a higher gear, clutch is in, and you downshift to 1st. Seems to only be in that 1-2 gate. Once you are in 1st and shift to 2nd it does not make the noise. IF you just sit and row through the gears the noise only appears when going back to that 1-2 gate. I've never been happy with the shifting compared to my old Golf, but this noise has popped up this Spring.

Since the bumper to bumper is soon expiring I thought I'd get an opinion here, before wasting time at the dealer.

 

[Scrubbydo1]

Definitely go to the dealer


Sent from my iPhone using Tapatalk

 

[jbower2010]

I second that.

Definitely go to the dealer


Sent from my iPhone using Tapatalk

 

[JPinSTL]

OK, took the car to the dealer. They had it 4 days. Car is "operating as designed" and no noise was heard. Seriously this noise was not there when new or the first 20,000 miles. I've been driving a manual for the last 30yrs and not even the old VW Bug was this noticeable. The noise is subtle I admit, but I'd think noticeable by a mechanic? The car still shifts as well as it did new, not Euro quality smoothness, but better than my Ford Truck

So just drive it until it gets worse or something fails? Cruze has 30,000 on it currently.

Anyone else have clunky shifting in their manual?

 

[JPinSTL]

Made an Appt last week for a ride along with a mechanic. Guy was really nice. He seemed knowledgeable and agreed that the shudder in a high torque situation when pulling a hill was unusual. He also was able to hear the clunk I was hearing when shifting. This was a different mechanic than worked on the car when they had it 4 days with no results. I'm dropping it off tomorrow for another shot. My thoughts are the shudder is the DMF and the clunk is the slave cylinder.

 

[Slayinit]

Yep, it's a pretty crappy gearbox. Google "Getrag M32". I dumped the factory gear oil early on just because GM/Getrag apparently under fills these things leaving 6th. gear starving for oil. Sure enough, I only drained 2qts. Refilled it with 2.5 qts. of Redline MT-85. Didn't change shift quality (I really don't think you can much) but at least I have peace of mind that 6th gear is fed.. hopefully. Good luck with your dealer & car. Unfortunately, I think this is normal operation for this tranny.

 

[Scrubbydo1]

If you buy a replacement clutch delay valve assembly and remove the delay valve orifice, it gets rid of the 1-2 grind 90%. If you add the short throw shifter the grind is erased. I put in synchromesh 5w30, short shifter, and delay orifice removal makes it shift like my b7 a4 did


Sent from my iPhone using Tapatalk

 

[JPinSTL]

OK this trip to the dealer was 2 days. They feel the vibration under torque, but have no idea what it is. They put a tech request to GM Corp. The local dealers claim is that they've never seen a 6spd, much less the diesel version, so they have no base reference for what is normal. I get that to an extent. but the vibration is getting worse. I guess that's a good thing as it will get ugly enough to fail. I personally think its a bad DMF. The shudder/vibration feels to me like when a torque converter is slipping in an automatic. I have the car back while they wait for GM.

They did not address the shifter clunk on this trip. I figure once they get a ruling and replace the flywheel the shifter will get resolved at the same time.

I took the car into a St Louis Dealer for this vibration issue at about 15K, they had it 2 days, and could not duplicate it. Operating as designed . . . Figured I might get better service locally so I went to our small town dealer, but they don't have the experience with this config.

@Scrubbydo1 once I'm out of warranty I plan to address the delay valve issue. I've never been happy with the way this car shifts.

 

[Arrest_me_redcruze]

If you buy a replacement clutch delay valve assembly and remove the delay valve orifice, it gets rid of the 1-2 grind 90%. If you add the short throw shifter the grind is erased. I put in synchromesh 5w30, short shifter, and delay orifice removal makes it shift like my b7 a4 did


Sent from my iPhone using Tapatalk

many chance you have a part number for that delay valve? Having a hard time finding it.

 

[JPinSTL]

OK, I think this has been resolved. Short story: bad axle half shaft!!

After striking out with the convenient to me dealers I dropped an email to the original dealer I purchased from. I asked them about what if any dealer they would recommend to look at this unicorn diesel manual tranny. There suggestions was themselves, Roger Jennings Inc. in Hillsboro, IL | Your Greenville, Springfield, and Litchfield, IL Buick and Chevrolet Dealer Alternative the only one they would trust. So even though about 2.5hrs from home I talked with the service manager, setup a mechanic ride along.

The vibration had been slowly getting worse and I was now at 45K. 3 min drive, 1st hill, little torque, guy was like oh yeah feels like a half shaft bearing. Prior to this I'd been thinking flywheel. So we head back to the dealer. They racked it, rotated the tires, checked the axle, took it for a ride with a "pico" vibration tester, and I was there about 3hrs. Likely conclusion was an axle shaft, but they'd plan to keep the car a few days just to be sure. They would order parts and I went home. Few days later, parts came in, and they called to arrange a loaner that I was to keep until the car was fixed. My work is about half way between home and the dealer, so they had their driver bring the loaner to me and we traded out. They kept the car a couple days, supposedly the inner bearing fell out when they pulled the axle shaft. Replaced it and no more vibe. Rinse/Repeat on returning my car, their driver came to my work an hour plus from them. RogerJennings in Hillsboro, IL has EXCELLENT CUSTOMER SERVICE!!!