Transmission Slipping

[AirJordan613]

So I took it to both my local Chevy dealer and an independent transmission shop. Both were able to reproduce the symptoms but neither observed a slip when they had their scanners hooked up. And neither recommended rebuilding the trans, but didn’t know what else could be causing this issue. Recently during a “slip” I seem to have momentarily lost electrical power. Dash flickered dark and airbag light came on for a few seconds afterward. Then returned to normal. Still mostly above 4k RPM but sometimes noticing a bit in upper 3000s. Anything electrical that could be causing this? The loss of power thing was bizarre. I’m pretty stumped myself. Hard to justify rebuilding the trans when two separate shops couldn’t confirm a bad trans.

 

[CaptainAmerica1]

Battery health? Checked the alternator? Pulled battery and cleaned and replaced grounds? Checks the battery cables for corrosion? All these tests are free and won’t change the fact your transmission may be toast but start ruling out the stuff you can check yourself….

 

[AirJordan613]

Battery is brand new. Grounds looked good last time I checked. Dealer recently checked those too.

 

[AirJordan613]

It certainly seems like there’s a transmission problem. Just scratching my head since both the trans shop and Chevy dealer thought the trans was mechanically OK.

 

[the blur]

Flushing a tranny with 140k. Nah... I'll pass.

 

[AirJordan613]

Flushing a tranny with 140k. Nah... I'll pass.

Your help is greatly appreciated…

 

[donjetman]

Flushing a tranny with 140k. Nah... I'll pass.

Your help is greatly appreciated…

While doing a rear main engine seal job, I changed the tranny filter and 100% of the fluid (Dexron6) in our very used new to us 132k mile Denali. 3yrs and 40k miles later it's still going strong.

 

[AirJordan613]

While doing a rear main engine seal job, I changed the tranny filter and 100% of the fluid (Dexron6) in our very used new to us 132k mile Denali. 3yrs and 40k miles later it's still going strong.

Glad to hear it! My tuner is going to take a look at it and see if there’s anything that can be corrected by tune. If not, I’ll probably just rebuild the trans.

 

[swathdiver]

Flushing a tranny with 140k. Nah... I'll pass.

Why not? This is not a TH350.

 

[mikeyss]

I'm just seeing this too, and that definitely should be checked out with a scanner soon. I see the CEL is not on, so the computer isn't detecting slippage between the input and output sensors. The thing my 6.2/6L80 has been doing is the shift flare between 2-3 shift and sometimes the 4-5 shift. I also hear my trans shift moreso than feel it shift