4l80e shift points

[rogers]

I had my tranny rebuilt while I was doing the engine. Now that everything is back together I have been paying more attention to where and when things happen. Specifically, I notice that the tranny shifts at 8mph and again at 15mph and again at about 25-30mph. If I have my foot down the shifts will be delayed by about 5mph. These seem like very early shift points. Is there something to be adjusted on the tranny or is it all in the KD computer I have? I am ashamed to admit that I really didn't pay much attention to the shift points before the rebuild, so that's why I ask. I'd like to hear from those with stock trucks and also those with reflashed computers. Is this normal?

[rogers]

Anyone? ... Bueller? Bueller?......

[john8662]

WOT Shift?

My 1996 shifts early, part of the programming, it's stock though.

My convertor lock is the one that makes it fall on it's face, which happens at 43mph, if I'm mid throttle it'll shift at 50 or 55 depending on how heavy.

Mostly I see shift occuring around the 2300 RPM range when accelerating moderatly.

J

[JohnC]

Shift points are all computer controlled. On mechanical pumps there is a throttle sensor that can be adjusted. On electronic pumps it's, well, electronic.

[Robyn]

4L80 will shift under light throttle, 1-2 at around 10mph 2-3 at around 20-25 and the 3-4 around 35 and then the lockup at 43-45

A moderate throttle will delay these numbers a bit.

What you are seeing is about normal.

Throttle pressure is the deciding factor in the final location of a particular shift point.

The early rigs with the DB2 (92-93 6.5) had a TPS on the pump that could be adjusted some.
The tranmission controls on the early rigs were a little less sofisticated.

The 94 and later trucks get all the signals from the APP sensor.

Depending on what butt gears are in the rig will change the shift points a little.

The numbers I mentioned are common with 4.10, 3.73 will be slightly later all the way through the range including the lockup.


Sounds like your rig is doing what its supposed to.

I am going out here in a bit in DaHoooley and I will pay real close attention to the exact numbers.

My truck has 4.10 gears so it will give us a good comparison.

I do know that light throttle lockup is 43 MPH right on the button

Missy

[Robyn]

OK

Just got back from the store.

95 GMC 3500 (DaHooooley) 6.5 with 4L80, stock tires for a 3500
4.10 gears.

Level ground with very light throttle.
1-2 shift @ 12 mph
2-3 shift @ 18 mph
3-4 shift @ 29 mph
lockup @ 43 MPH

Moderate throttle will bump the shift points up considerably and full throttle will really make it howl

Missy