Not sure if this is a trans or tune issue......

My track logs show that when commanding shifts at 5800, they were quick and actually executed at 6000 RPM. When commanding shifts at 6500, I was hitting my ETC rev limiter at 7000RPM and shifts did not execute until the throttles closed, likely based on the part throttle tables. I don't see anything obvious in the tune that would prevent the upshift at higher RPM. The trans did seem to be working alright except for the fact that when I went to test the D1 brake the switch did nothing. Have never launched off the brake. The wiring/switch tested good. Any thoughts?

In the video linked below there are 3 runs shot with a Go Pro inside the truck. The first starts around 1:50 in (10.99 ET)and was with shifts commanded at 6500. You can hear the throttle dip at each shift. The final run starts around 5:20 in and was with shifts commanded at 5800. You can hear the quicker shifts with no throttle dip. You can also hear the rear u-joint let go after the 2-3 shift! Video

 

My under standing is that this is the nature of the best with the 4L80E and a segment swap.

You have to program the shift prior to what you want it to actually shift at.

I believe the relay method of doing the 4L80E swap allows for a faster shift.

I have not done the swap yet my self so maybe some one who has can comment on that.

 

Welcome to the club.

I've had mine commanded all the way down to 4600rpm and it still overshot the 6000rpm shift point. It seems to be directly related to power. If I run 10psi or below, it shifts fine. But If I turn it up past that, it just doesn't shift until I let all the way out of the throttle.

 

Pretty sure its dependent on the PCM. Mine is segment swapped and hits the shift on the dot every time. Maybe I got lucky.

 

I've kind of noticed a trend in these stories where most of the stock or stock rebuild 80e suffer from this. Where as all the performance built 80e's never have this problem. OP, who build your trans?

 

my truck does the same thing with my segment swapped 80e

 

Oddly enough my 1-2 shift happens before the PCM should command it... Very weird.

 

Mine is on the dot also.

 

Extreme Automatics Stage 3 with bell and brake.

It doesn't look like it was intending to shift at all when I was running in Performance/Tow-Haul mode and commanded was 6500. I think it only shifted after the the rev limiter closed the throttles and it dropped back down into the non-WOT shift tables.

Didn't feel or sound like anything was slipping. Seemed to be holding the whole time it was overshooting.

Here is the shift when commanded was 5800. Actually shifts at 6000 and throttle stays at 99%.



Here is the shift when commanded at 6500. You can see that it runs to 7000, then the throttles close and re-open over a period of .35 sec. This was during my 10.99 ET run. I was wondering why people were saying it sounded like I was letting up on the throttle.

 

I did have to lower mine a little bit as I made more power. Can you log the gear to see if it is commanding a shift? That should tell you if it is a PCM issue or a tranny issue.