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Delayed 1-2 Shift, False Neutral/stuck 2nd On 2-3 Shift

yzav8r

By yzav8r
in Ask A GM Technician

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yzav8r New Member

yzav8r

Posted
Posted

Hi All,

 

Having a bit of an issue with the truck lately (2001 Sierra 1500 ECSB 4.8/4L60E/4x4 Autotrac). The 1-2 upshift has been a little 'slippy' as of late, as well as the 2-3, but only when it's really cold outside.

 

Today it progressed into a delayed 1-2 upshift, then at the 2-3 upshift it'll feel like a false neutral, but when I really hit the gas it seems that second gear is still engaged. Fluid level is good, is still red, and doesn't smell burnt at all.

 

This has happened before with another transmission (which ended up getting swapped out), and I'm curious to find if it could be ECM related (even though the dealer and a tranny shop said that it was fine and commanded all the shifts like it should be).

 

But, from what I can read this is either clutch pack/band issue or that the 'B' solenoid isn't bleeding off. Any thoughts before I shotgun some repairs or throw a different transmission in there?

 

 

 

 

Thanks in advance!

yzav8r New Member

yzav8r

Posted
  • Author
Posted

I did a little more checking and found out the following.

 

I can get 2nd gear, only while in Drive, if I'm going over 27mph and let off the gas to allow the shift. If I'm gentle on the throttle through about 45, I can hammer down and carry this all the way up to about 80, where the 3rd gear shift should be forced. There's no shift though, it just hangs in second and doesn't upshift.

 

If I get on the throttle too hard and hit the kick down, it falls back to a false neutral/1st gear state.

 

The false neutral/1st gear state also occurs if I manually select 2nd or 3rd, and also if I enable Tow-Haul.

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