wamara

I'm looking at 2017 Silverado and Sierra 1500 series trucks, and could conceivably order one with the 8 speed transmission. My impression is that the 6 speeds are pretty bulletproof (am I right?) but am concerned about any teething problems with the 8 speed.
Any (cogent ) input would be appreciated. Thanks in advance

I see there is a post here about the A8s; I don't know if there is anything to add?

94Lt1Vette

I have 22,000 miles on my 2015 Silverado and it has been a POS transmission. Just replaced the torque converter last week.

Shifts hard, sometimes has to search for the gears, etc. It's a little better since the replacement, but I haven't driven it enough yet (it's still doing a relearn).

MVR 155

I've got a 2015 Yukon Denali with the 6.2L/8 speed drivetrain...... Its been flawless to date, with the DOD and 8 cogs it could be a bit quicker to respond but it's a minor complaint.

wamara

Hmm, looks like 50/50 so far.... Are the 6 spds considered reliable? This might be the safer way to go

rgregory

I have a 2010 Tahoe with the 6spd. I have 148,000 miles on it now, no issues with the transmission. I have changed the fluid (drain pan, fill it up and drive then repeat again) 3 times and the filter at one of those changes at like 50,000. I do not believe in back flushing.

I had to install a drain plug in the pan as it did not have one from factory. I think it is time for a change again it is starting to shift a little funny. I do think had I never changed the fluid the trans would not be working like it is, this goes for any car.

Even my previous Tahoe with the 4 spd it would start to act funny after about 40,000 miles on the fluid, so changed it whenever acted funny. It had 110,000 miles when got rid of it but no trans issues.

wamara

rgregory, sounds like good advice regarding the trannie flush for future reference Did you have to tap the pan to install the plug ?

rgregory

The pan is sheet metal so can't Tap it. I bought one of those drain plugs from the "help" section at the autoparts store that you drill a hole in the pan and bolt it through. It is pretty cheesy but dropping the pan to drain is such a mess. The first change of fluid/filter change I had to drop the pan anyway so did it then.

Doing the drain, refill and drive, then repeat has cured mine and friends transmissions from acting funny and it is easy. On the Tahoe it is 4 quarts that come out of the pan. So it takes 8 quarts to do it.

Mopar Jimmy

All I can say the A8 in my 2016 C7 Z06 had a catastrophic failure with 6,200 miles on it requiring a brand new trans. and converter. Not sure if that is the same 8 speed auto going in the trucks but needless to say I don't have much confidence about the new A8 trans. in the C7 Z06.

TurboTnZ06

I have both 6 speeds in trucks sububans and most recently a 15 1500 crew Denali 4x4 6.2 8 speed. The 8 speed is awesome. I want the 10 speed coming out next. Only downside is the factory 3.23 gears, with it was 4.11's then it'd be even more awesome.

Bucknut2006

The 8 speed in my in-laws 2015 Tahoe is not the greatest. Does a lot of gear hunting and hard shifting. It's a very frustrating experience when we are in the mountains.

rgregory

How many miles do they have on it? My 2001 Tahoe with the 4spd I had to change the fluid at 40,000 miles when it started to shift funny and hard shifts at times.

My 2010 with the 6spd I just changed the fluid again today since it was doing hard shifts and now it is all smooth again 148,000 miles on it. It does seem like 40-60k is the max for the fluid in my experience.

Bucknut2006

Started around 2k and it may have 10k on it total now. The entire driveline, rear end and rear suspension was also fully replaced. Basically everything from the drive shaft back that is connected to the body.

Zoomin

Mine has had a few episodes where it slams into gear after what feels like a slip in stop and go traffic. One time it hit so hard I looked in the rear view mirror to see if I had been hit. Just turned 10,000 miles in my 16 Silverado.

Like TurboTNZ06 said, if it had 4:11's it would be perfect otherwise.

rgregory

Why did they change the rear end if the transmission is shifting hard? So they didn't change the transmission? That is way to low of mileage to have problems that sucks.

danziger

I have had the A6 in two GMC 1500 Sierras...they were absolutely bombproof. Would buy again.

Silverspeed

Thanks, but neither one of these posts have anything to do with the 8 speed transmission. Your posts are the equivalent of me saying the the 3 speed auto in my 82 Z28 was great. It has zero relevance.

I have a 16 Yukon Denali with the 8 speed, and I would call it average at best. Anyone who has driven any Lexus with an 8 speed would know why I say that. From a stop, at full throttle, or 50% throttle it is great. At low throttle it is not. I wouldn't call the shifts "rough" per say, but they are not smooth. Crushing at 30 mph, and applying WOT, it is not responsive. There is a delay, probably from AFM, and shitty GM tuning. It could be much better.

SpeedUp

Is GM introducing the A10 because the A8 is such a turd?

Mopar Jimmy

Question for tranny dummies, is the A8 trans in the truck the same exact A8 trans used in the C7 Z06? With the Z06s 650 HP and TQ I would think that it has to use a beefier version of the A8 used in the trucks?

wamara

Wondering the same thing.... If it is the "same", I would suspect that while the hardware is the same, the software programming is different (although it is sounding like both the 8 speed 'vette and truck(s) have similar drivability issues).

danziger

If you looked at the OP, he asked if the 6-speeds were bullet-proof. The posts are there to answer his question.

No need to be condescending, especially when you are incorrect.