Back in 2014, this blog predicted a variety of problems related to then upcoming 8l90 transmission, one of those sounding on paper ideas, as long as the execution delivers on the promises.
So far, the variety of problems related to the new +General Motors 8l90 eight speed automatic transmission was already mind boggling: from expected overheating issues, failing flex plates, variety of leaks and software related issues, all the way to right down scary cases of transmission voluntarily "inspiring" new Corvettes to rev up and attempt to take off.
However, what was missing were the problems with the torque converter. Apparently, this is no longer the case and in fact, the torque converted problems are well on the way to become another Corvette issue of epidemic proportions, further eroding already weak faith the hardcore Corvette buyers may have in +General Motors and the ever popular +Tadge Juechter .
As expected, the undersized and high spinning torque converter issues manifest themselves in a shudder and jerky motion the car starts demonstrating, accompanied by fluctuating engine RPMs.
However, here lies the big problem: the same symptoms can be easily associated with the ever popular AFM forcing the newest Corvette into 4 cylinder mode. Given the inept nature of the typical GM dealership service department, those owners who are lucky to have their problem diagnosed correctly are an exception to the typical GM customer service rule, with the rest of the schmucks being told "it is all good and related to AFM", sending them back home on another shuddering ride.
Those who are fortunate, can find another dealer who can figure out the problem but others, are forced to either live with the problem (until it becomes unbearable) or sell their car altogether.
Of course, those who are lucky to have their car repaired are lucky only to a degree, the torque converter repair requires a complete transmission replacement and transmission replacement requires rather complete tear down of the drivetrain, including the rear end. Not only does the process take a long time but the chances of the dealer getting the car back together correctly are rather slim.
As this is the same ole GM, and with about 20k of 2015 and 2016 A8 Corvettes affected (until about end of October 2015 production dates), GM refused to alert any of the owners of the affected cars to offer a proactive solution, preventing further frustration while dealing with the service department.
Instead, GM chose to revise the components in the transmissions produced since November 2015, leaving the owners of the earlier cars totally screwed.
This truly shitty and unethical approach is not anything new, in fact, the exact one as with the owners of the previous generation C6 Z06: it is considerably cheaper to replace failed transmissions than take proactive approach and replaced all of the defective ones. After all, the torque converter problems require several thousands of miles to be put in on the newest Corvettes and plenty of buyers hardly drive their newest acquisitions. Thus, as usual, GM is doing absolute jack shit to accommodate the owners.
Has GM addressed the torque related problems with its 8l90 update? Even though simple components like seals and O-rings have been most likely upgraded to ones that can withstand higher operating temperatures, the transmission itself received no revision, thus, the same inferior torque converter is still included. Perhaps, the problems with the transmission will take a bit longer now but they still will be there, this is guaranteed, as long as the same torque converter is used.
totally Fckd ! but not expected. just like issues with the LS7 heads going kaput
ReplyDeletehere is a link to owners bitching about the 8L90 TC
ReplyDeletehttp://www.gm-trucks.com/forums/topic/167913-2015-8-speed-transmission-replaced-with-3000-miles-on-it/page-2
I have the suddering when afm is on at constant throttle rpm fluctuation of about 200 and noticing
ReplyDeleteJust had the torque converter replaced and problem not fixed. It has all the symptoms that are named plus the seatbelt has engaged twice while driving. Felt like got hit from behind.
ReplyDeleteThis car is certainly an eye-gasm , but until now I had no idea that it was a piece of shit. I guess gm hasn't changed a bit since I stopped buying them back in the 80s. Amazing to me is the fact that these morons have been able to keep this and other "recall-able" defects out of the media. Maybe if they put that hush money into R&D they wouldn't have these problems.
ReplyDeleteTook my 2015 to dealer today because of surging of transmission. They said that they agreed with my complaint and showed me a service advisory that basically said that GM was aware of the problem and to tell the customer that the surging and rough shifting was normal. The problem occurs in corvette, camaro and cadillac with lt1 and lt4 engines with 8 speed automatic transmission. Once again GM treats customers like crap and will think nothing of asking for taxpayers to bail them out when things go bad.
ReplyDeleteJust took my 2016 C7 to the dealer on 5/22 with what seems to be the torque converter issue being reported here. Car was knocking every 6 to 8 seconds while driving it on all driving modes. I can feel it in the wheel and the pedal also RPMs were up and down about 200 each time. Took to the dealer and they agreed with me after test driving car and said there was something wrong with trans. Called me today to tell me that it is the torque converter and that they are going to work on it. hopping the problem is fixed when I get car back
ReplyDeleteI have a 2016 camaro ss. Headed back for torque converter number 3 next week. Only lasted about 12k miles!!! Last chevy i buy. My last dodge put it to shame durability wise! Chevy should be ashamed!
ReplyDeleteI just started having the shuddering problem on my C7 with 3,600 miles. At this time it is intermittent. I dread taking it into Castriota in Port Richey for their usual fresh air,sunshine
ReplyDeleteand bird crap all over the car treatment then listen to the usual, 'they all do that' B.S..
My 2015 A8-equipped Corvette is at Sunset in Sarasota right now, having TC changed out for redesigned unit. This will include fresh transmission fluid and a new filter. Car has 8,000 miles on it but started showing signs of problems noted above as early as 2,000 miles. Hoping this is the fix. Service reps at Sunset have been first-class with me, told me their techs have done several other Corvettes with same problem and provided me with a new Malibu loaner vehicle. Further I can recommend the $199 plug-in device manufactured by Range Technology in Colorado (designed only for GM products) that over-rides AFM and keeps the engine running on 8 cylinders full time, exactly the way it was originally designed to do. AFM is a bunch of crap and makes virtually no difference in MPG. My Corvette does better than 29 MPG on the interstate with the Range device installed and the engine runs turbine-smooth.
ReplyDeleteAmen! The range device is a miracle. As stated, mileage is the same or better when in 8 cylinder mode. The owners manual states that the C7 will disable the AFM in Manual Mode! That's total BS! It doesn't do shit. The Range Device installed is day vs night in the stock mode of operation. Further, there is less force and pressure on bearings of the 4 cylinders when in 4 cylinder mode.
ReplyDeleteI took delivery of my 2015 C-7 with the 8 speed automatic on October 15, 2014. At 18k miles, my problems began. Thank goodness, I went to a New Smyrna Beach, FL dealership, and they knew exactly what my problem was. They replaced my transmission, no questions asked. At 32k miles, my problems started again; I took the car to the dealership where I purchased it, in Mississippi. After they had the car for a week, the told me it was the AFM problem that several have mentioned above. Of course, I had to take the car back. I actually put the transmission man in the car with me and show him how the car was doing. They say that they replaced the torque converter and my problem hasn't resurfaced yet, but I've only put about 500 miles on the car since that repair. One thing that makes me question whether the MS dealership really replaced the torque converter is that it is not mentioned on the service records for the dates in question, even after me asking them to enter them.
ReplyDeleteI have a 2015 corvette that was built late in 2014. At about 4000 miles I had the shuttering and lunging problem they put in a new torque converter and after a couple of thousand miles it is all coming back. Not good
ReplyDeleteI have a 2016 corvette and the shuttering problem started at 13,000 miles. My local dealership told me it was normal due to AFM. After writing a letter to GM about the issue, the TC was replaced and eventually a new transmission was installed at 17,000 miles. Everything worked fine until almost 30,000 miles on the car and the shudder is back just as bad, if not worse, than before. I just took the car to the dealership today so we will see what they say. I know it is the same issue as before and I'm disappointed that there does not seem to be a permanent fix. I have been wanting to trade the 2016 for a 2019 but I'm afraid the new ones still have the same issue after a certain number of miles because I don't think GM has actually fixed the problem.
ReplyDeleteIf you think GM fixed this defect, think again. The only way you can put the imminent headache is to look for a different car, preferably not GM
Delete