New Silverado owner 8-spd transmission Questions...

GravelPitsYew · June 3, 2020

Hey guys, I just came off 12 years in a Tundra Crewmax that I nursed + only drove about 6-7k per year...then engine failure at 85k! Lost my loyalty and now I'm back in my first truck brand from high school, Chevy.

Anyhow, I know there's a lawsuit from Silverado 1500 2014-2019 8-speed transmissions (model 8L90/M5U), but wondering if that has 1) been remedied for 2020 models, and 2) is that for both RWD + 4WD models (was reading the lawsuit and said "rear-wheel-drive" models but every 4WD is rear-wheel most of the time so I'm assuming same tranny)? So far my new 5/3L w/ 8-speed DFM drives great! Smooth gearing, way better than my tundra 6-spd in that dept. Did I just buy a lemon in the making?

GravelPitsYew · June 3, 2020

BTW, I have the 5.3L Silverado 1500 LT Z71 crew cab, std box.

JimCost2014 · June 3, 2020

38 minutes ago, Josh Gould said:

BTW, I have the 5.3L Silverado 1500 LT Z71 crew cab, std box.

No, the 8 speed is a very stout transmission, and with new fluids being used you should be just fine.

code-man26 · June 3, 2020

15 hours ago, Josh Gould said:

BTW, I have the 5.3L Silverado 1500 LT Z71 crew cab, std box.

I have the same setup as you do and have had the truck in twice now for transmission acting up. When I put it in drive and step on the accelerator, sometimes it lurches pops out of gear, then slams back into gear. Shakes the whole truck and gets attention in the parking lots. GM is telling me they are working on a new valve body replacement. A VALVE BODY REPLACEMENT ON A BRAN NEW VEHICLE!! IMO this 8spd transmission is junk. Good thing I still have my 2005 Duramax with 400,000 that's NEVER broke down or given me griefs. EVER!

Lawsnook · June 4, 2020

If the 2019 8 speed does not have the problem does that mean it has the new updated/different fluid.

My 2019 RST has less than 800 miles. The dealer told me yesterday they have not had the problem with 2019. But, when I take off from a stop especially when everything has not warmed up, it feels like I am going over a rough road. It’s a shudder. I also felt a VERY harsh down shift when I had to stop quickly at the end of a highway off ramp.

I’m thinking the problem has not been solved or I have a different problem. I will say this is the first vehicle of any kind that has a transmission with more than 5 speeds and most have been 4 speeds.

The last truck I had was a 92 F-150. So, maybe I’m not used to how these transmissions shift. But, I have had a lot of vehicles and driven a lot of miles, so I THINK I know when something doesn’t feel right.

GravelPitsYew · June 4, 2020

Thanks for the replies so far guys. I only got the truck last weekend so I'm still under 200 miles. So far the thing shifts smooth! Way better than my 6-spd 5.7L tundra. Power-wise, I know the tundra has 380hp but this 355hp seems faster, maybe it's just the added shifts enabling it to shift sooner between gears. I've been watching the "TFL Truck" youtube page and they had the 8-spd beating the 10-spd in 1/4-mile race, just an fyi. I do really hope this thing lasts without that issue. Only time/miles will tell.

tinbad · June 5, 2020

The 8 speed in my 2019 TB is pretty much the only thing that I haven’t had issues with. I had a few hard shifts the first couple hundred miles but has been shifting smooth ever since.

krb49 · July 28, 2020

I have 2019 Sierra, 5.3, sometimes it has a very significant delay when going from park to reverse or reverse to drive, then when it engages feels like the rear end is coming out of it. Real evident “bang or thud” when it finally engages. Problem is it doesn’t do it all the time. Service told me they aren’t aware of anything or any tsb’s.
Anyone point me in the right direction if there are any tsb’s? I’m not aware of the lawsuit mentioned previously either. Thanks

Edited July 28, 2020 by krb49

Gangly · July 28, 2020

Sometime around March of 2019 GM announced it was primarily a transmission fluid ordeal where the fluid absorbed water. The issue was corrected and the transmission stutter and hard downshifts were basically resolved on late 2019 models. I haven't heard of any issues on 2020 models. My 2020 5.3 8-speed shifts through the gears like a hot knife through butter, so smooth you wouldn't know it was shifting. On infrequent occasions when just starting the cold vehicle and pulling up to the stop sign at the end of my street, a slightly harder downshift from 2nd to 1st is barely noticeable, so much so that I doubt a passenger would notice it. Nothing to notice with the transmission beyond that.

Basically, if you have a 2020, or late production 2019, you're good to go. The 8 speed transmission has proven to be an excellent transmission now that it's sorted out, and 1st through 3rd gears (4.56, 2.97, 2.08) are a BLAST! I'm not one to speed on public roadways, but the gearing in these transmissions make it far more exciting to accelerate up to the speed limit than in previous versions of the truck. It really makes me wonder about how much fun you can have with the 6.2 and the 10 speed transmission.

Edited July 28, 2020 by Gangly

yogi89 · July 30, 2020

On 7/27/2020 at 9:41 PM, krb49 said:

I have 2019 Sierra, 5.3, sometimes it has a very significant delay when going from park to reverse or reverse to drive, then when it engages feels like the rear end is coming out of it. Real evident “bang or thud” when it finally engages. Problem is it doesn’t do it all the time. Service told me they aren’t aware of anything or any tsb’s.
Anyone point me in the right direction if there are any tsb’s? I’m not aware of the lawsuit mentioned previously either. Thanks

I am having the same issues in reverse. If my truck sits in the garage for a week or more and I start it up there is a delay like it is slipping when I put the vehicle in reverse. Have had it in once but of course, did not act up for them.

Giantpeaches · July 30, 2020

On 6/4/2020 at 9:51 AM, Lawsnook said:

If the 2019 8 speed does not have the problem does that mean it has the new updated/different fluid.

My 2019 RST has less than 800 miles. The dealer told me yesterday they have not had the problem with 2019. But, when I take off from a stop especially when everything has not warmed up, it feels like I am going over a rough road. It’s a shudder. I also felt a VERY harsh down shift when I had to stop quickly at the end of a highway off ramp.

I’m thinking the problem has not been solved or I have a different problem. I will say this is the first vehicle of any kind that has a transmission with more than 5 speeds and most have been 4 speeds.

The last truck I had was a 92 F-150. So, maybe I’m not used to how these transmissions shift. But, I have had a lot of vehicles and driven a lot of miles, so I THINK I know when something doesn’t feel right.

Yeah I have this too but ironically, only does it when I leave work and thought it was the road then I drove my girlfriend's car on the same road and it was smooth.

Ron Allmand · July 31, 2020

1st post to the forum - wanted to use a social media outlet to get some feedback/advice on whats happening with my 2020 TrailBoss.

I have always been a Chevy guy - and I bought my TrailBoss in December 2019 - it only has 3,335 miles and around 21hrs or so on the engine.

I went away for a while and leased some luxury sport sedans for almost a decade. I came back to truck life with this purchase. There have been 3 or 4 recalls & dealership service visits (annoying but ok). Now - a real issue!

- on tuesday (28 July) I dropped off to dealer with these symptoms:

- (July 25th) Started up truck and backed down my sloped driveway to my cul de sac (auto) - engine revved to aprox 4200 rpm after shifting into drive & did not go forward (no gas pedal applied) - after 15 seconds or so I pressed the gas pedal and truck barely moved forward (like it was pulling a trailer but it was not under load).

- Service Engine light on

- Disabled the auto start/stop function, no real results. (still sluggish/high rpm) Hwy speed 70mph at 4200 rpms! (Called dealer from the road - setup appointment to drop it off) jerky shifting parking up my sloped driveway.

- (July 26th) engine light on - shifted into drive (truck did not move forward) - high rpms - engine light turns off - pulled back up driveway and truck rpms revved and jerked forward.

- (July 28th) 8:30am drove the 8.2 miles to dealer (no engine light) rpms at a comfortable 1200 @ 70 mph on the freeway | check fuel light comes on with estimated 31 mile range. Did NOT stop for gas and left it with the dealer.

- (July 28th) service rep calls to state that my truck is the next one in line to see their transmission tech (Garrett) but it might not get seen today. [OK]

- (July 27th) no update from the dealer

- (July 29th) no update from the dealer

-(July 30th) 8:00am call dealer (my svc rep not there) he states that truck was out of gas and they needed to put in some fuel for a test drive and then they would get it over to their transmission guy? He says those notes were from 7:15 that morning. 3:00pm I decide to pay them a visit, service rep calls Garrett directly and he states the transmission is out of the truck and he found metal shavings in the "pan" - he is ordering parts for a throttle body (for replacement)

- (July 31st) 8:30am my svc rep calls (was out last three days) and was surprised no one had called me to update - we confirmed about the throttle body and parts were gong to take 4 days to arrive.

SO - any advise on this - I have read so many 8 speed transmission issues that I am concerned and am looking to possibly dump this truck for the 10sp version. Love to hear input | experience from the forum.

Thanks