Trans issues

[docrabbit]

I hate my first post is like this but I need advice. I bought my 2015 Silverado Z71 Crew Cab 2 days ago. So stoked about this purchase. Less that 20 miles on it out the lot and now has 100 miles on it and the shifting is atrocious. I have a lag in between 1st and 2nd gears then a decent lag coming down from 3rd. There's a 1 second or so delay in acceleration when I step on the pedal after stops. Up hill acceleration blows and lags. Lag lag lag.

 

There isn't any clunking, not sure what to think. I checked the VIN and no recalls. Thoughts guys? I have read the threads on here, all the horror stories and I have a bad feeling.

 

First new truck, first big purchase. Could be panicking for nothing.. But.. Want to be safe.

[txchevy4ever]

Give it at least 500 miles. The computer is still in learning more for the shift points.

[310racing]

I know this isn't the answer you're looking for, but suggestion would be to program it. It does need to learn shift points, but the trucks are programmed to get to 6th gear as quick as possible, which to me made to truck feel like a slug.

I went with a Diablo canned tune, MUCH better, I love driving it now. Black Bear would be even better.

Not gonna get into the warranty discussion, Im just saying, if you want a much better driving experience, tune.

[EastCoast HD]

First....

 

Congrats on the new truck

 

 

How many miles on it?

 

Drive it like you stole it for the first tank.

 

Should help.

[pm26]

I hate my first post is like this but I need advice. I bought my 2015 Silverado Z71 Crew Cab 2 days ago. So stoked about this purchase. Less that 20 miles on it out the lot and now has 100 miles on it and the shifting is atrocious. I have a lag in between 1st and 2nd gears then a decent lag coming down from 3rd. There's a 1 second or so delay in acceleration when I step on the pedal after stops. Up hill acceleration blows and lags. Lag lag lag.

 

There isn't any clunking, not sure what to think. I checked the VIN and no recalls. Thoughts guys? I have read the threads on here, all the horror stories and I have a bad feeling.

 

First new truck, first big purchase. Could be panicking for nothing.. But.. Want to be safe.

Does not seem like you took any of them seriously.

[newdude]

I'd give it 500-1000 miles. Let it learn your habits and keep in touch with the dealer if need be. If it doesn't improve in that time frame, see if they can reprogram the truck for shift concerns and have their transmissions guy go for a ride if need be.

 

Otherwise you will love that truck!

[SilveradoX2]

I manual shift my 2013 all the time after reading another thread in the Full Size area for the 2013's. When we buy a 2015 later the year (because the NHT package is just coming out) I'll manual shift that dude too even though I'm not trailering.

[docrabbit]

I will do the 500 mile suggestion and consider a tune after that. With what I've read GM isn't being real responsive to this issue so my patience with my dealer will be short lived.

[wurgs]

My truck used to have some of the same issues mentioned on here but after about 1000 miles they seem to have disappeared, I think the talk about the tranny having a learning curve is true. I haven't noticed it hunting gears or any clunking in the last 200 miles. There is still a slight delay in the 1-2 shift but am sure it's just the torque management.

[TJay74]

There are several adaptive learning tables in the TCM that take time to adjust. As said I would not baby it, drive the truck as you will. That means going WOT at times so the TCM learns those habits.

[CounterMeasure]

The learning period is not some "X miles" time, but going through a bunch of different conditions. For example, there are tables for high altitude versus sea level. If you live in one of those environments, and never go to the other, your transmission never finishes "learning". If you road trip in it to some new place, then it can see a new scenario and be in "learn" for it. The ballpark number usually given is 500 miles, because it is believed that will catch most city and highway driving at different operating temps and so forth in its home area. I learned this because I am one of those horror stories, and have become more knowledgeable about the 8L90 in my truck than I really wanted to.

 

If the erratic behavior in the early miles bothers you, dealerships have a way of doing a "fast learn" procedure. They can tell which scenarios the transmission still needs to build values for, and put the transmission in a mode and run very specific cases to get the tables filled out in less time than you running around in it. I know this because they spent a few miles doing that on my replacement transmission to do what they could to validate it was problem free in normal driving conditions before giving it back to me.

[docrabbit]

Thanks for the input you all, I appreciate it

[f8l vnm]

My 2014 is still trying to learn @ 5400 miles lol

I'm not going to turn this into bitch fest but the learn thing IMO is bs. The slow speed driving of this truck is horrid.

Does it take forever to get into 6th as well ?

[TJay74]

The learning (it is called adaptive learning) is not BS. I have seen the tables in the calibration and they are there. You could always have the dealer reset your adaptive trans values and then either have them do the fast adapt process or start driving it again. Don't baby it, when you baby it is when it causes issues with shifting performance.

[f8l vnm]

Either way , low speed driving needs to be fixed. I agree this happens when I "baby" it. But There are instances where u have to drive slow. my house is on a uphill with speed bumps every few hundred feet. It's impossible not to baby it.

Or what about in neighborhoods with kids playing ? Or parking lots? The 20-30 mph trans confusion is something I have never experienced before. How is this fixed?