Weird Issue Hard To Explain

[SpThomass]

Hey guys! For starters I have an 06 Yukon denali XL, 6.0, 223k miles!

i posted about this back in December, and it’s hard to explain, but basically when driving after a dead stop (red light or something) when going into second it just loves to hold onto first for some reason. Other than that it feels perfect, no hard shifts, weird feelings, or sounds.

I’ve tried cleaning the TB and the MAF but those didn’t seem to work. I’m thinking the TPS but I’m not sure how to test it. Obviously the tranny is anyone’s first guess, but this literally happened overnight and I’ve changed the fluid about a month ago and it’s not burnt or anything, as well as no metal specs in the old fluid.

here’s a video of before the problem and after:

Any help is appreciated!

 

[SpThomass]

The whine in the second video is my steering gear dying lol. Before this started, it would shift into second perfectly without the unnecessary high rpms and the about to explode feeling. Now, no matter how I’m pushing on the pedal (hard or soft) it does this.

Also, there’s no codes and no CEL. I’ve also noticed that if I let it shift on its own it does the high rev thing, but if I let off the pedal completely, the revs drop and it shifts into second immediately and without issue.

 

[wjburken]

Looks to me like you have a valve sticking in your transmission, but I am by no means a transmission expert.

 

[OneofFew]

There is lots of info out there to diagnose these transmissions. Possibly 1-2 shift solenoid.

 

[SpThomass]

There is lots of info out there to diagnose these transmissions. Possibly 1-2 shift solenoid.

Thanks man, I just keep searching for anything related to this issue but I can’t find anything. But thanks for giving me something too look further into!

 

[OR VietVet]

Might need to check on this servo from Oregon Performance Transmission: https://www.oregonperformancetransmission.com/product/SNX-77911-03K.html

Does sound like a transmission specialist needs to look at it though.

 

[adventurenali92]

That is definitely revving way to high before going out of first gear into second! When you described it in your other thread, I thought it was revving maybe to like 3000 RPMs befor shifting, not nearly redlining! Honestly with the transmission there are so many things that COULD be going on. It’s hard to tell but I think a trip to a transmission shop is in order at least to get a look at what’s causing it to rev that high.

 

[SnowDrifter]

Has me wondering about the throttle position sensor....

Hook a scanner up and check live data

Gearing/tire size/speedometer combo all accurate?

 

[SpThomass]

That is definitely revving way to high before going out of first gear into second! When you described it in your other thread, I thought it was revving maybe to like 3000 RPMs befor shifting, not nearly redlining! Honestly with the transmission there are so many things that COULD be going on. It’s hard to tell but I think a trip to a transmission shop is in order at least to get a look at what’s causing it to rev that high.

Sorry for the late reply man, I haven’t been feeling well so I haven’t been on. I took it to my mechanic who’s worked on it for over a year now and when he did the fluid change he said everything looked fine, no specs in the fluid/pan, it was dirty but because it had been a while since I had it changed. I’m probably going to get an appointment with him to check the TPS and the 1-2 solenoid.

 

[SpThomass]

Has me wondering about the throttle position sensor....

Hook a scanner up and check live data

Gearing/tire size/speedometer combo all accurate?

Sorry for the late reply, haven’t been feeling well. But I assume so, everything drive train related is stock for now atleast. Everything on it now has been there since the problem started. And that’s what I was thinking too, the TPS.