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Discussion Starter #1
I have been having a couple of issues lately and I am trying to get them sorted out. I am not sure if they are electrical (wiring or tuning) or mechanical issues.

I have a Jake's Stage 5 4L80 with a D3 transbrake. From his website, this includes a billet input shaft, billet rollerized forward hub, billet intermediate shaft, and 36 element sprag Super Drum and his D3 brake. I have had this a couple of years and I am guessing I have 2500 miles on it.

This is in a heavy F-body (3900lb raceweight), 3.25 rear gear, and MT Pro Radial Tire (28.2" tall). The transmission is electronically controlled through Holley Dominator.

I am looking to solve 2 issues.

The first, the car does not want to make a 1-2 shift at WOT. It goes right past the commanded shift point, hits the rev limiter, and eventually shifts from 1st to 3rd.

I have tried adjusting the WOT shift RPM and also have tried different Shift Tables. It didn't seem to help. It is difficult to test on the street because of the power on the 1-2. Currently, the car is down, but looking to see whether people think there is something mechanically in the transmission, or electrically in the tune.



The image above is from my latest track outing. The WOT shift was set at 6500 on the 1-2 shift. I eventually pedaled the car and then got back into it in 3rd gear. I have a transducer on the 4L80 and this is labeled "4L80 Pressure". The thing that stands out to me is how the pressure is falling off around 5800 RPMs.



The image above shows the burnout from the pass above. This shows the transmission shifting as it should at part throttle.



The image above is a screen shot from the Transmission Setup in Holley from the pass above.



The image above is a screen shot of the Shift Parameters from the pass above.

I have also tried lowering the 1-2 WOT RPM to 5800.

This is a screenshot of that pass:


I added the transducer between the passes. The pass at the top was recently in August versus this one directly above that was in July.

Looking to see where we can go with this. I can try to post the Data Logs if needed.


Problem #2:

When I engage the transbrake, the car rolls forward before actually engaging. To offset this temporarily, I engage the TB, hold the brake pedal and start to apply throttle. From there I release the brake and it holds to fully apply throttle.

I have found this thread with a similar situation: http://www.yellowbullet.com/forum/showthread.php?t=1028994

I wired a relay to cut power to the EPC as discussed in that thread. However, I wasn't seeing the results.

The latest pass shows the 4L80 pressure for this:

The pressure actually goes down slightly when the Transbrake is engaged. Then as I bring in throttle, it jumps.

Any ideas on either? Could they be related?

Also posted in the Transmission section.

Any help is much appreciated.
 

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When you are testing this, is the car in traction on the 1-2 shift? I remember tuning my 4l80e in my truck on the street and if it was spinning at the shift it would never follow commanded protocol.
 

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Discussion Starter #3
When you are testing this, is the car in traction on the 1-2 shift? I remember tuning my 4l80e in my truck on the street and if it was spinning at the shift it would never follow commanded protocol.
Data Logs above were both from Track passes. Full traction. The latest pass was a 1.27 60'. Can see at the end of the Data Log when traction is lost (83mph).

There is a traction problem on the street though. Even on wastegate.
 

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Discussion Starter #6
Talked to Jake with Jake's Performance on the phone and gave me a few things to try.

Will be a little bit but will post up with feedback.

Thanks again Jake. Top notch customer service again for me!
 

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What ended up being the issue/fix. Having a very similar issue with the same trans and holley setup and would like to know what you found.
 

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What ended up being the issue/fix. Having a very similar issue with the same trans and holley setup and would like to know what you found.
Intermediate clutches. Had the transmission freshened and works as it should.
 
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