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Thoughts and Feedback on 8-speed Transmission: Should I Be Concerned?


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On 6/18/2019 at 10:41 PM, aaronk said:

I'm thinking of jumping ship from a Tundra to a Silverado, but the 8 speed that I drove was noticeably clunky compared to my Tundra.  I love everything about the 1500 but the 8 speed scares the crap out me.  The searches on forums and Facebook groups leave me feeling real uneasy about pulling the trigger on one or waiting to see if the 10 speed is offered for the 5.3 in 2020.

The 8-speed tends to have a 1-2 "bump" during the first shift when cold. This is because the clutch needs to fill with fluid as it makes that shift. It's normal. A brand new transmission needs to "learn", so between being cold and just beginning to "learn", it's going to be a tad clunky like the one your drove. The first 2019 Silverado 8-speed I test drove was more clunky than the 2019 truck I ended up taking home. So far aside from the 1-2 bump shift in the morning, mine has been smooth. GM's shift learning tends to be sensitive to sudden changes in driving style. It doesn't hurt anything, it can just bother people that aren't use to a slight bump sensation.

 

If you wait for the 2020 trucks to arrive in a month or two, you can get a 6.2 truck with the 10-speed in a cheaper RST or Trail Boss trim. I don't think the 5.3 will get the 10-speed in the 2020 models.

Edited by HondaHawkGT
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4 hours ago, HondaHawkGT said:

The 8-speed shudder in older trucks was fixed. The shudder issue was being caused by the transmission fluid's coefficient of friction changing over time as it absorbed moisture. Exxon Mobil reformulated Dexron HP to address the moisture issue and the shudder should a problem of the past.

Thanks HondaHawkGT. Good to know I shouldn’t have to worry about the shudder this time around with my 19. 

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For what it's worth, I had a 2016 5.3 8spd, it was kind of notchy, when cold mainly. Never really bothered me and as I drove I became more accustomed to it. Never had any kind of shudder. Lease was up with 40k on the odo. Went into a 19 and it is much smoother, when cold hits a little hard on 1-2. Honestly I like the 16 feel better, when it shifted...it did with authority. I think the 8spd is fine and have confidence in it.

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I was worried about getting the 8 speed mostly from reading this forum you’d almost think the 5.3/8 speed is some sort of afterthought that GM decided to throw in the mix just to differentiate the lower trims. When I placed my order the 10 speed wasn’t announced yet. Yes, I could’ve waited another 4 months and paid more to get into a ‘20...  Boy am I glad I didn’t. The 5.3 with the 8 speed is very quick and smooth. Apart from folks who have transmission issues due to some legitimate defects I believe the majority of complaints seem to be coming from folks who just traded their S-class for a Chevy lol. 

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On ‎7‎/‎6‎/‎2019 at 11:31 AM, shakazulu12 said:

5.3 can be had with the 10 speed in the 2020's on trims from the RST up.

GM autobook states 2020 RST's still have 5.3L 8-speeds. It says you have to get a TB to get the 5.3L 10-speed. Stupid. All LT and up with the DFM 5.3's should come with the 10-speed.

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If you drive with the truck in L8 it’s like a completely different truck. I think a lot of the problems are with cylinder deactivation and transmission tuning working together. Even braking is different with it in L8, presumably because it has all 8 cylinders worth of torque. Now every time I drive it’s in L8 and I like the truck. The transmission was seriously about to put me over the edge and I was considering going back to Ram. Now I think I’ll hang on for a bit and see what happens.  


I believe myself this could be the issue, because when the truck is under load accelerating under all cylinders it shifts just fine.
I noticed all the weird shifts and clunks are when DFM is doing its thing. With a loud exhaust I can tell when DFM is working.

I’m anxiously waiting for a tuning company to make a DFM disable module of some sort.
I have 13.5k miles on my 2019 Z71


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My Trail Boss LT 8 speed is not worrying me completely but it has quirks.  Mainly shifting from reverse to drive there is a delayed upshift after it starts moving, very hard bang which is unnerving.  Also, the hard downshift.  BUT it's got 7k miles, and has been smooth most of the last 3-4k miles.  Either the adaptives are still learning or the warmer weather helps.  It's going to be under warranty long enough I'm not losing sleep over it right now.   But the 4l60 had problems, so does the 6l90, and so does the 10 speed, pick your poison.  

Edited by Leevon
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  • 2 weeks later...
On 08/07/2019 at 2:48 PM, Leevon said:

My Trail Boss LT 8 speed is not worrying me completely but it has quirks.  Mainly shifting from reverse to drive there is a delayed upshift after it starts moving, very hard bang which is unnerving.  Also, the hard downshift.  BUT it's got 7k miles, and has been smooth most of the last 3-4k miles.  Either the adaptives are still learning or the warmer weather helps.  It's going to be under warranty long enough I'm not losing sleep over it right now.   But the 4l60 had problems, so does the 6l90, and so does the 10 speed, pick your poison.  

Could you say more on the 10 speed issues, please? 

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I have a hair over 600 miles on my LT Z71.

The tranny- the truck has just been magnificent to be honest. The only thing I can gig it on, and as mentioned in an earlier post, when shes cold and you first start out, it may change a little hard from like 1st to 2nd. I've only felt it do that 2 times.

I was able to put 200 miles in one day, and did some interstate driving. She was wonderful at 80 mph or more!!

And just very good all around to be honest.

I live in the highest elevations in the Blue Ridge Mountains, and we have a lot of rural up and down country roads as you might imagine. This truck has never once had to search for the right gear or whatever. Just very smooth, seamless shifting. I love how its goes thru the gears when I drive her.

The new 2019 Silverado is super fun to drive. 

Hope that helps

 

 

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