3rd gear transmission issue

[t.stimpson]

My truck seems to float slowly into 3rd gear. I have read there is an issue with this on alot of these trucks. Anyone try the repair and did that fix it? Mine does this intermitingly. I have also noticed when in tow/haul mode it downshifts into 3rd rather abruptly and too soon. The engine revs pretty high when this happens. Can any of this be fixed by software/computer tuning?

 

[t.stimpson]

bump.

 

[DenaliScott]

What truck and motor do you have?

Some people have had good luck with the software tunes. Are you under any warranty? If so, take it in.
It could be a good sign that it's intermittent.

I just took my 2010 Yukon Denali 6.2 in yesterday for my trans flaring or slipping between 3rd and 4th. 71,000 with no abuse. No issues until yesterday but I was getting the high rev then it would click into gear. It's getting a full rebuild now under factory powertrain warranty.

 

[t.stimpson]

its a 2009 yukon xl denali with 6.2l. not sure of the transmission. I know its a 6 speed. it has 108K miles so no longer under warranty.

 

[ccapehartusarmyINF.(ret)]

probably the 6l80E wich i heard has alot of problems its like the only tranny without a direct drive gear wich is usually 3rd wich has a 1:1 ratio
the 6l80e has 3rd gear 1:1.5 ratio and a 4th 1:1.15 then 5th and 6th are over drive gears

 

[Speck]

I just had the same problem today while towing on my 08 Denali. i am also on my second transmission after the first grenaded while being worked on at the dealership at 72k miles as well. At this point i'm going to start looking for after market tuning for the transmission to fix the shift points. I wish I had help for you, but I can definitely feel your pain.

Joe

 

[t.stimpson]

@Speck, i read a forum on chevy camaros which i guess have the same engine/transmission and some on there were trying to get rid of the problem with tuning. Some were successful but others never seemed to get the problems to disappear for very long. They would tune it and then the problem would return in a week or so otherwise I would have gone this route. Tuning is expensive especially if no guranteed results. I may just have to live with it.

 

[Speck]

Thanks Tyler, I may hold off and see how it does. I do notice that it only occurs when in the tow/haul mode. I do plan on doing some engine mods in the future, so I may hold off on tuning until that happens. Best of luck with your issue as well.

Joe