2nd Gear Slip on 5.3L Uphill

icetime · October 11, 2013

I am new to the board, have a 2014 Sierra SLT with just 1k miles. Have been driving very conservative while breaking things in, for the most part.

Today though, I was driving uphill and decided to put some foot into it, and noticed that coming out of 2nd gear, the shift to 3rd felt like the tranny was slipping before engaging in 3rd (at least that's how I can describe it, even though its automatic). I tried it two other times today (again, on the uphill, say 5-6% grade) and it is repeatable. I think this is occurring about 30mph or so (I'd have to confirm). On lesser grades or the flat, I don't experience this. I have a 3.08 axle ratio.

Is this a defect? Has anyone else seen this?

Any insight appreciated.

mzodarg · October 11, 2013

Welcome aboard! I have not experienced that as of yet. I've taken mine up some steep grades. Mines a 4x4 with a 3.42 rear end in it with 4k on the clock. I'm wondering if this is all part of the transmission learning your driving style?????

Mike

C25A1guy · October 11, 2013

Maybe that slip is from the tire? I do notice that these trucks are very easy to break loose. Prime example of my smokey burnout at my warehouse last night.

GMC-AT · October 11, 2013

Mine started getting better at around 1,200 miles. Only 2K now... hope it continues to "learn" something new! I hate the trans in these trucks..

icetime · October 11, 2013

It could be something to do with the trans 'learning' mode, as suggested (I hope), but definitely not the tires breaking loose. Has more to do with the uphill grade, than just pure acceleration, it seems. Not sure why it would be the 2nd-3rd gear shift only, and not any others. I guess this is one I'll pose to the dealer on the next service interval. Thanks for the welcome guys (appreciate the comments)!

GMCustomerService · October 11, 2013

icetime,

Congratulations and welcome to the forum! Just wanted to stop by and let you know that GM Customer Care is here on the forum and happy to assist if you ever have any general questions or concerns about GM products.

Safe travels,

Jennifer T.

GM Customer Care

icetime · October 12, 2013

Good to know GM is monitoring for issues here. If I run into some enduring issue, it's good to know that someone from GM is 'listening'. Thanks again for the welcome.

Joe_K · October 12, 2013

I am new to the board, have a 2014 Sierra SLT with just 1k miles. Have been driving very conservative while breaking things in, for the most part.

Today though, I was driving uphill and decided to put some foot into it, and noticed that coming out of 2nd gear, the shift to 3rd felt like the tranny was slipping before engaging in 3rd (at least that's how I can describe it, even though its automatic). I tried it two other times today (again, on the uphill, say 5-6% grade) and it is repeatable. I think this is occurring about 30mph or so (I'd have to confirm). On lesser grades or the flat, I don't experience this. I have a 3.08 axle ratio.

Is this a defect? Has anyone else seen this?

Any insight appreciated.

I have the same axle ratio as you and have not experienced that at all. All shifts are crisp and firm, especially when I give it some throttle. I would definitely take it to the dealer.

GMCustomerService · October 13, 2013

icetime,

You are welcome! We are happy to assist anytime you may need our assistance.

Regards,

Jennifer T.

GM Customer Care

Natek · October 13, 2013

I would wait 5,000 miles before I mentioned anything about the transmission. I'm sure it's just learning. Drive it like you normally drive during this period or it will have to relearn again.

icetime · October 15, 2013

Thanks everyone. I will wait and see how the tranny learning mode goes based on your comments here. Good to have the support system here.

DanielAcosta · November 6, 2013

I am new to the board, have a 2014 Sierra SLT with just 1k miles. Have been driving very conservative while breaking things in, for the most part.

Today though, I was driving uphill and decided to put some foot into it, and noticed that coming out of 2nd gear, the shift to 3rd felt like the tranny was slipping before engaging in 3rd (at least that's how I can describe it, even though its automatic). I tried it two other times today (again, on the uphill, say 5-6% grade) and it is repeatable. I think this is occurring about 30mph or so (I'd have to confirm). On lesser grades or the flat, I don't experience this. I have a 3.08 axle ratio.

Is this a defect? Has anyone else seen this?

Any insight appreciated.

I noticed drivability issues like you describe when test driving 3.08's, none with the 3.42's. There is also an ECM update that specifically addresses shifting and drivability. The dealer applied it to my truck even though I was having no problems because my VIN fit the range of those affected according to GM. Suggest visiting your dealer and telling them you'd like an ECM update for drivability.

BTW, there is also a newer ECM update for the AFM. Both updates can be done at the same time, takes about an hour. Good luck.

racinjason14 · July 25, 2017

I have a 2016 and it has done that since the 3rd day I owned it to current. That's been since 7-1-2016 and it doesn't get better with more miles. I have 24,500 and it still does it and I have piles of paperwork from the dealer and I keep being told it's normal. This is my first vehicle I've bought new and it's a nightmare so far. I have 30 years in the automotive field as a tech. To me it's not normal along with the hitching under a load grade or no grade. It hitches like you have plug wires off. Another issue that I'm told has to done at GMs level do to it being in the programming. Have had open reports with GM and I was told they were working on it. Hope they come up with something fast for the transmission issue. I'm going to one and done if not.

njk4o5 · July 25, 2017

its just the crappy transmission tuning that comes in these trucks...totally normal

elementaltoad · July 25, 2017

You might also be mistaking the pause during an upshift for slip too? The 6 speed in these trucks really reminds me of the way my old Duramax with the Allison 5 speed shifted. There is a fuel cut I believe, tuned in that reduces power during the shift to prevent transmission damage. It can feel odd especially up going up hill when it shifts, and will send you toward the steering wheel during a shift if you aren't used to it. The Duramax would bounce your face off the steering wheel between WOT shifts.