4L60E 2-3 flare

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Morten

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Hi all,

after weeks of searching information about my problem I now come to seek help here.

I have a tahoe 1996 k1500 5.7 with the 4L60E transmission in it, the truck has allmost 170000miles on it, I got it used so don't know it's history, but the service book shows GM has done more or less all the service...

If the truck is cold it will shift fine with light/medium/heavy throttle... but after a few minutes with light throttle it will make a small shift flare of 200-300rpm going from 2nd to 3rd, and this will continue at every 2-3 shift with light throttle until the truck cools down again, but if medium/heavy throttle is applied it will shift fine?

The transmission oil is at max and is nice and clean, does not smell burnt.

Truck is almost stock, besides 3 inch lift in the back and about 1 inch in the front, and 33" tires, so it is higher in the back, can this do anything bad, thinking less oil in the back, more in front?

I live in europe, and there is not many american trucks here so I am a little on my own...

Can it be as simple as a sticking shift valve?

This is not my truck but my problem is the same when hot (or atleast not cold):
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Regards Morten
 

skylark

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Sometimes a half of a quart over full will solve this problem. I have a similar problem with a tranny that was fine when I pulled it about 5 years ago. I just installed it and it has the flare under heavy throttle. I'm going to replace the 2-3 shift valve with the Sonnex HD version. Most likely it is just sticking.
 

Supercharged111

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I thought the 2-3 flare was a fairly common issue that the Transgo shift kit was designed to address.
 

df2x4

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I thought the 2-3 flare was a fairly common issue that the Transgo shift kit was designed to address.

Or in my case, a warning sign that the 3-4 frictions are about burned up... Again...
 

Morten

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Thanks for the replys.

Extra oil in the transmission - I thought that was to solve flare if you had the problem under heavy throttle, bacause of the oil going to the back of the transmission?

Is it also to help under light throttle?

Regards Morten
 

Kran

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in my opinion every 4l60e should have a shift kit from TransGO or Superior Transmissions installed.
 

Overtime

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Flare between shifts is a sign of worn under/over rev clutches. Add a half-quart of fluid and see if that helps, if it does help then think about adding a shift kit.

I have driven 4L60's that flared for 100k miles and some for 1k miles before they gave up.
 

Morten

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Flare between shifts is a sign of worn under/over rev clutches. Add a half-quart of fluid and see if that helps, if it does help then think about adding a shift kit.

I have driven 4L60's that flared for 100k miles and some for 1k miles before they gave up.

Thanks, I will try adding oil to the transmission, the weather is really bad here right now but will hopefully try this weekend.

I still think that is does not necessarily needs to be the worn clutches, as the transmission does not flare beside the 2-3 shift at light throttle.

Regards Morten
 

Morten

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Added extra oil to the transmission, I only had 1/4 of a quart but it did not change anything:-(

I will get some more and see if it helps.

Did read that some says a dirty maf sensor can make the transmission slip, does this sound possible? If I unplug the sensor should it give the transmission full pressure?

Regards Morten
 
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