Weird Issue Hard To Explain

[sonic_the_hedgeh]

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!

I don't have any error codes on my 04 yukon denali and yet it won't shift from first unless I let off the throttle. So I bought a transgo kit and talked to a shop today and he said I don't have a second gear because he was shifting manually. I have tested my tps but seems fine.

But yet others have had the same problems and installed the transgo kit and it fixed the shifting problems. Yet this shop says they doubt it needs a rebuild and bands must be worn. Yet he cannot verify why it seems to shift from 1st to 3rd gear.

Any ideas? I was told this kit a bought for my 04 yukon would fix it.

It is a 4l65e, this kit fixes the 65 and 60 trans.

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