I wrote earlier about my transmission (2021 Delivered in August 2021) woes. Twice I lost odd gears, though it rectified itself a few miles down the road. But each time I took it to a dealer I trust. First time, service manager cleared codes and CEL. Since it drove and shifted fine, I went on my way, both of us hoping it resolved itself. Then exact same thing happed again. Again it fixed itself about five miles of driving, and again took it to the dealership. This time, we scheduled a service appointment. Well, today was my service appointment. And wouldn’t you know it, it did the same thing. Loss of odd gears and CEL. Which was rather fortuitous since he would have the current codes available. Again, I regained all gears after about five miles after leaving home on my way to the dealership.

I arrived at the dealership, manager read the codes and drove it to the service area. I was planning on leaving it at least overnight. My wife meet me to drive back, but we looked at the appearal, and bought a nice hat (oh, and I put a $1,000 refundable deposit down on an eRay, at MRSP, seventh on the list, but that’s another story for another forum).
.

So to the guts of the story. Since I took my time leaving, I stopped to check in with the service manager before leaving. Good thing I did. He stated the tech had done another C8 transmission with same symptoms. He said he’s ordering a transmission module and once it comes in (when it comes in is the $64 question) he’ll schedule appointment for the install. I asked about the flush and fresh filter. He stated GM has their procedure, and the module is the next step. I was surprised he would do that before the flush, but who am I too argue? I even brought my own filter and two quarts of transmission fluid should they not have them in stock. But it was not needed. (The two quarts were for adding, if they were topping up the lost fluid from on top rather than by the check hole by the axle. If it was convenient, I wished then to add the two quarts. Couldn’t hurt, maybe help. But not necessary today.)

So now I await for the transmission module. If that doesn’t do it, I then get to stand in line for a new transmission. Oh well, as of now, the car runs fine, but I am cautious that this may happen again, leaving me stranded. Even though I am in Wisconsin, I do drive it as long as the roads are clear. One reason I did not get the Z-51, I wanted the all season tires. Got sick of changing over twice a year with my C6.

Hope to hear from you concerning this. Thanks all.

 

It's evolving for them too and they do check in with GM tech support on these issues. On the surface I too would think a flush would be the first step, but GM is figuring these out day by day and maybe they have enough history that if this then that. Keep us posted on the resolution.

 

When they change the module does it get all new fluid and filter? Or just parts out and new parts in ?

 

My C8 Has a leaky transmission (No CEL's). Found out after seeing small amount of fluid in the garage floor. Dealer tested to determine where leaks were coming from and ordered new transmission under warranty. Car has been at the dealer since December 16th. Told Transmissions are back ordered with no arrival date provided. Anyone have the transmission replaced on a C8 and how long did you wait?

 

Me, I would drive the car until they call and tell me the transmission has arrived.

 

It wont be long until the class action lawsuits start popping up on yet another turd GM transmission design. Oh that's right GM doesn't warranty design defects...

 

GM didn’t design this transmission.
On another note you seem to be really unhappy with everything about your C8. First you went ballistic when it didn’t ship as fast as you wanted and you even filed a complaint. Then ever since you have been constantly complaining about something with your car or GM. The constant complaining gets old. I can’t speak for others but I really enjoy this forum and I come on here to share info and yes even shortcomings and issues. Bashing GM and Corvettes is not what I think any of us enjoy. This is only a suggestion but now would be a great time to sell your C8. You can make money and go buy something that you will be happy with. It’s a win win situation for everyone.
Please don’t take this as an attack on you because that’s not my intention. I just hate to see you so unhappy when there are other options.

 

Just had mine replaced and it took 5.5 weeks to get, but I was able to keep the car garaged at home. I did not drive it as I only had even number gears. Due to weather, I have only been able to put 150 or so miles on breaking it in, but it's working fine so far. You can try calling GM Customer Assistance 800-222-1020 and see if they can speed things up. Good luck.

 

So how do you explain that GM has not denied ONE warranty claim on them?????

 

Honestly, I would have driven the car until the new transmission arrived.

 

Mine's leaking and I drive mine, weather permitting.

 

Smurf has posted 295 times in his first 2 months on the board, most were complaints.

 

Yeah but he's a tease, he asked if we should really do business with a company like GM. If he just sells his car maybe he can be happy somewhere else.

 

Same thing I'd do, up until the day they are ready for me to bring it in for the replacement

 

My question is, did your dealer first replace the module per the first post above by mazurekd?

"... So to the guts of the story. Since I took my time leaving, I stopped to check in with the service manager before leaving. Good thing I did. He stated the tech had done another C8 transmission with same symptoms. He said he’s ordering a transmission module and once it comes in (when it comes in is the $64 question) he’ll schedule appointment for the install. I asked about the flush and fresh filter. He stated GM has their procedure, and the module is the next step. I was surprised he would do that before the flush, but who am I too argue? I even brought my own filter and two quarts of transmission fluid should they not have them in stock. But it was not needed. (The two quarts were for adding, if they were topping up the lost fluid from on top rather than by the check hole by the axle. If it was convenient, I wished then to add the two quarts. Couldn’t hurt, maybe help. But not necessary today.)

So now I await for the transmission module. If that doesn’t do it, I then get to stand in line for a new transmission. ..." posted by mazurekd

 

You don’t say!

 

Came to post same but was too late. I don't get you, Smurf, you were kinda funny insisting on driving up to BGA to peak under hundreds of C8 covers looking for yours. Since then though you've gone into this dark-side d-bag funk. WTF?

 

OP here. As stated, car runs good…for now. As in the prior two times after it lost odd gears and then rectified itself. I will drive it, sparingly, as advised, until it really acts up. I am glad I didn’t hibernate the car, because if I did, I wouldn’t know of this problem, and would have delayed it till spring/summer. If I need to lay it up, best let it be in winter. As soon as I hear anything new, I’ll post.

 

Good luck with your transmission replacement buddy

 

Sorry you are having problems with your C8. Hope GM can get the transmission module to your dealer quickly and then the dealership can get your car repaired.