hesitation shifting into 1st or reverse

[Ophthos]

I have a 2015 Yukon Denali. From the get go I noticed that when I turn the truck on and shift into 1st or reverse, I have to wait a second or two otherwise the transmission will "slam" into gear. It doesn't mater if the engine is hot or cold.

The only fix I've found is once you start the truck, let the tach and speedo swing all the way to the right and settle. Sort of let the engine start up and settle for a second.

I've had my dealer look at it and they reset the TCM. It did seem better for a bit, however, after a week or two the issue is back.

Its going in for a different issue with the heated seats not working, but I was going to ask them to look at the transmission again, any thoughts?

 

[jl449]

I have a 2015 Yukon Denali. From the get go I noticed that when I turn the truck on and shift into 1st or reverse, I have to wait a second or two otherwise the transmission will "slam" into gear. It doesn't mater if the engine is hot or cold.

The only fix I've found is once you start the truck, let the tach and speedo swing all the way to the right and settle. Sort of let the engine start up and settle for a second.

I've had my dealer look at it and they reset the TCM. It did seem better for a bit, however, after a week or two the issue is back.

Its going in for a different issue with the heated seats not working, but I was going to ask them to look at the transmission again, any thoughts?

Took our 2015i 8spd in for a dead AC compressor at 24k miles and since then noticed an issue with trans.

There are some updates that were done to the car like the speed limits now being on HUD which weren't there before.

However, the bad is that the car now shutters and bumps harshly into reverse every time it is selected, either cold or warmed up. Forward shifts are fine.

I hope there is a software patch for this.

Any others out there?

The car has never been to the dealer since new BC I do my own servicing and has been great up to now.

Thx


Sent from my iPhone using Tapatalk

1st generation 8spd (vehicle manufactured before ~march '15) had issues with the transmission.
I had simular issues (gear slop and hesitation engaging in 1st) and had the transmission replaced and problem solved. Well the replacement only lasted less than a week but the 3rd unit is still going strong!


http://www.tahoeyukonforum.com/threads/clunk-noise-at-acceleration-until-warms-up.71265/

http://www.tahoeyukonforum.com/threads/8-speed-transmission-software-flash.69755/page-3#post-914390

 

[Ophthos]

Thanks for the input. Mine was made after March and I don't have any of the "slippage" issues people noticed while driving. Nor do I feel any clunking while driving. My transmission shifts fine up and down at all speeds. I only notice a hard shift from Park if I start the truck and immediately put it in gear. Give it a second or two after starting....all is fine.

I'll see what the dealer has to say.

 

[Shadow17]

I was just going to start a post on this, but glad I came across this one. Mine has done this from the start and I mentioned it again at this oil change.
They reflashed the TCM on the prior oil change and it worked for a couple months. Now it's back to slamming again when cold. I always start my truck for at least a minute prior to driving via key fob and it seems to help.
The only other thing I notice is it likes to slam a bit when downshifting or if I am driving around 45mph and shift the tranny into manual mode.
Last night my wife even mentioned how she felt it clunk when slowing down for a traffic circle.
She asked me, "What did you do?" I just told her it's the stupid transmission and thank God it's only leased until next year. smh

 

[Miami-Dade]

I only notice a hard shift from Park if I start the truck and immediately put it in gear. Give it a second or two after starting....all is fine.

I'll see what the dealer has to say.

The dealer is going to say there is nothing wrong with it..Just wait 30-45 seconds after starting it cold before putting in gear and you will be good to go.

 

[HiHoeSilver]

Why are you trying to put it in gear before the idle even stabilizes?

 

[Shadow17]

Why are you trying to put it in gear before the idle even stabilizes?

I think what the OP means is when shifting into gear you need to keep your foot on the brake for about 2-3 seconds or the truck lurches forward. That's what mine does, but only when it is cold. I believe the high idle causes it to happen.
The problem I have occasionally when it is warm is the truck will float between gears, almost as if it is neutral. Sometimes if I don't wait the engine will rev until it finds the gear and then goes.
My G8 had similar issues until I did a TCM tune.