Weird transmission Issues

[SafetyGuy]

Fairly new to posting here,

 

I have a 2012 Sierra 4x4 4.8L. 

I'll take you back almost a year ago, I was taking the family somewhere in my truck and stopped for gas. The truck was off for approx 5 mins while I fueled like I normally do. I started the truck cleared my odometer like I always do and put it in drive and proceeded to pull out of the gas station.  I was immediately greeted with the hardest 1-2 shift I have ever experienced, I continued down the road thinking that was strange and had to stop at the next light. The same thing happens almost like the tranny is shifting at full line pressure. The shifts were so hard that the tires wanted to slip.

I felt like the tranny was going so I drove it to our location and it sat for around 20 mins. 

 

I got back in and everything was back to normal. Shifting fine nothing out of the normal. Checked for codes and there was nothing pending.

 

Fast forward to this morning. 

Started the truck with a remote start, ran for 2 mins and I jumped in, Forgot to put my keys in the ignition and went to shift into gear and the truck shut off. I restarted with the keys  ( like I should have) and proceeded down the driveway where I was once again greeted with full line pressure for the shift. This time it was with all gears but felt more pronounced with the 1-2. I tried pressing the tow haul button to see if this changed anything and it didn't. I pulled over shut the truck off and restarted with no change.

I continued driving to work and stopped for gas, the truck was off for approx 5 mins and started up and everything is back to normal.

 

I don't know if this is a computer glitch or if its a sign of the transmission failure.

The fluid is a nice reddish pinkish color and the fluid level is spot on. Transmission temp was normal.

 

 

Any advice? 

 

 

[mjm-1957]

What trans is it?4l60E or 6L80E?

[SafetyGuy]

4L60E.. Forgot to mention truck has 180 000 km on it

[O_J_Simpson]

Start saving money.

[pronstar]

I would take it in and have it looked at.

It could be an adjustment or solenoid or something like that.

If they say you need a new tranny, keep driving it until it fails.


Sent from my iPhone using Tapatalk Pro

[carkhz316]

Have it scanned for codes. I wouldn't be surprised if it has a P1870 (trans component slippage) code or similar. If it does, it will default to a limp mode of sorts, with full line pressure, which explains the driveability issues you're experiencing. 

[nqabigt]

My 08 4l60 has done this 6/7 times since new, 120.000+ miles

first time it happened in a heavy downpour, the next time, dry weather

the dealer was useless, unless broken parts are obvious

it has rained hard all year, has not done it in the past 20,000 miles+

it happened twice in one week!

the next time , pull over and shut it off for 2/3 minutes {Works for me}

I would not worry about it, unless it becomes chronic

[nqabigt]

forgot to add, no codes

[SafetyGuy]

On 10/5/2018 at 10:17 AM, nqabigt said:

My 08 4l60 has done this 6/7 times since new, 120.000+ miles

first time it happened in a heavy downpour, the next time, dry weather

the dealer was useless, unless broken parts are obvious

it has rained hard all year, has not done it in the past 20,000 miles+

it happened twice in one week!

the next time , pull over and shut it off for 2/3 minutes {Works for me}

I would not worry about it, unless it becomes chronic

Glad to know I'm not the only one.

Seems to be an odd issue and the fact that is can be fixed by letting the truck sit for a couple mins is strange.

[Black02Silverado]

Just curious but has the fluid ever been changed along with the filter?

[nqabigt]

9 hours ago, Black02Silverado said:

Just curious but has the fluid ever been changed along with the filter?

I've dropped my pan twice and new filter+ 5 + qts, installed a drain plug 

now i drain and replace 3 1/2 qts yearly, shifts better than new {amsoil of course}

[JRoc]

I've seen this issue fixed with a new throttle position sensor it was an older truck but still the 4l60E.

[Tammy20002500]

When mine did this, it turned out to be low on Fluid. The dipstick said it was fine with the bottom 1/3 of the hash marks covered. Went to 3 Tranny shops with no one able to offer a solution.. I randomly threw in a quart for for Sh1ts & giggles. Turns out it needed 2quarts, and all was well.

[p8ntballa9362]

mine did that, but only after super long trips (2hrs+) throught the mountains and shit. alot of shifting up and down etc. seemed like it was only 1-2 though. and after i turned the truck off and let it cool for a few hours it was fine again.

[Jarekz15]

https://www.youtube.com/watch?v=IZjcPMzUhIU

https://www.youtube.com/watch?v=thtdwTJH4XY

Something to look into