01WS6/tamu

iTrader: (36)

Took my 2011 on long trip to colorado over the last week. It did great up in the mountains tow haul is the cats meow for going down mountain road grades and corner. Performed like a top clean up to 10000+ feet above sea level. For us texas people pretty damm high.

But anyways after about 13 hours on the road yesterday of no shutdown steady driving save for gas stops on the way home I noticed the shifts getting soft between 2,3,4. But you could manual shift it to the respective gears and floor it with traction control disabled and it would not slip a bit once it was in the respective gears.

From a dead stop with traction off if you nail it she was having nasty slippage between 2,3,4,5 gears but never slipped a bit once in gear. The trans temps were averaging around 180-190 the whole way home in 100+ degree heat. It's on a 100% stock tune on the engine and transmission and I was not towing but was averaging around 80-95 for the majority of the trip.

A friend on mine has a 5.3 version of my truck and drives out to west texas all of the time for work where it's on the road 8+ hours at a stretch and in the past he has complained about the exact identical thing on his truck but I didn't know what to tell him. yesterday on the way home I called him and my truck was acting exactly like his slip for slip. His is stone stock as well

This morning it will not slip a bit and no codes according to tech2 at the shop. Is it just time for a tune to up the line pressure and shift points and make it shift like gm should have made it instead of the slush box mushy shifts it has. Or is she on the way out.

Usually when we swap them at work they are FRIED already and wont move from my experience it feels like a low oil pressure issue during the shifts that's causing the problem and not a tranny failing.

Ideas thoughts or cures thanks?

1slow01Z71

iTrader: (36)

Sounds like a pressure issue to me. I know its apples to oranges but when I had the built 60e in my Z71 if I got on it already in the gear I needed to be in on nitrous it wouldn't slip. If it had to downshift or I ran it through a gear where it shifted into the next one it would slip through the shift. Add 10% line pressure and it shifted like a champ.

1slow01Z71

iTrader: (36)

You might also try adding a trucool trans cooler. The denser cooler fluid will add a little pressure too. I'd do that first since it sounds like its a temperature related issue.

Area47

the lower the temps on the 6l the lower the pressure. if it's 100% stock, i wouldn't worry about it. if it tanks, let gm fix it.

1FastBrick

iTrader: (17)

I don't think you could go wrong by tweaking the factory tune. I would be curious though about the Tranny temps. Especially with such a long drive and running it through the mountains.

I don't have any documentation on the new trans So I don't know what the service intervals are. I would be curious How often they require a filter change or fluid service Vs were you are at in mileage.

01WS6/tamu

iTrader: (36)

It has 8200 miles. It was sub 4000 before I left on our vacation trip in it. It's stone stock on both the engine and trans tune. Only truck mods are the drop.

I did do a junkyard find full volant cold air intake but have not tuned for it and it's not popping any codes. Is there a snow ***** chance in hell it could somehow be causing a trans slip between shifts.

I've been planning on doing a tru-cool on it.

Area47

the air flow increase across the maf and skewing of the fuel trims does have an effect on the trans and how it shifts. torque calc based

01WS6/tamu

iTrader: (36)