Hi guys, I am struggling with my 411 computer, lq4, 4l80e 2005 dbw combo. I am using EFI Live to make changes, and am quite satisfied with it. I have the convertor clutch engaging roughly halfway through third gear, moderate throttle, and would like it to stay engaged on the 3-4 shift. I can't get the convertor to completely unlock prior to shifting 3-4 even with the shift lock disabled, so I thought, just leave it engaged. I set the box to "yes" in parameters, tcc, where it gives the choice, but the computer still unlocks, then relocks the convertor after the shift. This causes an annoying "hunting" and multiple shifts on the 3-4. The 3-4 is not harsh, but a nice quick shift, so I don't feel it's abusive on parts.
Really, the question is, has anybody had trouble getting the computer to cooperate in asking for the convertor to remain locked on an upshift? I put my scan tool in it to be sure, and it's being commanded to unlock, then relock. Thoughts?

 

I've never tried it. Always set them up to not lock during a shift. Since I've never done it I don't have first hand info, but I hear it's hard on the input shaft. Probably break it.

 

If the converter clutch isn't built to be locked under abusive conditions I would try to avoid it.

I have mine set to not lock the clutch in 3rd gear at all. Problem solved. Anytime I am cruising the car will pass 3rd into 4th before locking the converter for seconds will have time to affect fuel mileage at all anyway.

 

Shift extension is your friend unless you have a real
lousy or mismatched converter. You should hit into
significant torque multiplication which you'd lose if
(truly) locked. And whether the converter really wants
to be locked at WOT, even though it's a 4L80, is a
question for your vendor.

 

My question was never intended to be a "do you suggest I try this" or "will my convertor handle it if I...." I am asking if anyone has tried, in the software, to get the pcm to leave the pwm convertor clutch solenoid engaged on an upshift. What is the point in having the option in the tuning tables if it still doesn't do it when commanded?

This is a bone stock 2500 pickup, and the convertor engages in third from the factory. I replaced the convertor (stock hd rebuild) due to a chatter on apply when the trans was cold, and got fussing over how it shifts. I put in a Transgo blue box shift kit, and licensed the pcm to my efi live v2, and have been messing around with it, getting more experience. Tranny shifts fantastic, but the one thing I can't get right is the 3-4 and the convertor clutch timing. It doesn't shift really harsh with the convertor locked, no harder than the 1-2 without it locked, so I don't feel it's abusive. But after it shifts the 3-4, the convertor unlocks and relocks again. Annoying, so I am trying to remedy it.

My 2500 dodge diesel makes about 900 hp and 1600 ft. lbs, and shifting that with the convertor locked makes it a couple tenths faster in the quarter, so I don't exactly agree on the torque multiplication making it faster overall. It hasn't broken yet, and this little gas motor will never make that torque or weigh that much, so....

Plus, during a hard 3-4 acceleration, the convertor is not locked anyways; I am interested in the light throttle, normal driving area of the tune. Anybody else?

 

So I thought about this for a while today, and tried an idea I came up with. I made the 3-4 shift TIME slower, slower than stock, at light throttle normal acceleration, and the trans has time to dump the convertor before engaging fourth gear. I then get what feels like A 5 speed trans, with third lockup splitting the difference between 3 and 4. About a second after 4th is applied, the convertor clutch comes back on, and all seems normal.

The question still remains, why when I command the convertor to stay engaged during a shift does the computer still command it to disengage? Strange..... I have spoken to other guys locally that lock the convertor in the middle of second, and the car picks up, usually 1-2 tenths. Seems this would be more common, but IDK.....

 

All operating systems have a lot of parameters we can't edit using commercial tuning software. Some of them are the cause of problems like this, sometimes there are workarounds but sometimes there aren't

You can try flashing a different OS to your PCM and copy all your current parameters to it to see if it fixes the issue. Usually a newer OS fixes a lot of issues

If you are sure your tune isn't to blame and can't solve the problem with the resources you have access to, send an email to HPT support for a review. Most of the times they are able to find a hidden table or parameter which solves the problem. You need to provide them with a lot of details, like your current tune, several datalogs, etc.

 

Bill at HP has been fantastic with support and questions; unfortunately I am using EFI on this project. So, unless I start over.... I wonder if I can get in touch with Ross.... Gotta contact Cindy.... I'll be back.

 

Any updates on this? I'm having the same issue, (and I'm using EFI Live) I am commanding my converter to lock in second and it unlocks, shifts into third, and relocks.

 

Look at the 5.7, 4.8, 6.0, and 8.1 Express van 4L80E tunes. They almost all LOCK 2nd gear at WOT and upshift at part throttle with a locked converter 2-3 and 3-4.

 

True, but those motors aren't making 600 hp either. I'm just concerned about shaft breakage.

 

Guys I know who want to lock 3 rd gear while racing can't rely on the PCM settings. So they hard wire in a switch and do it manually.
Maybe you could do that and see if you even like the result?

 

So in getting back to my little truck tuning project here..... I bought a MPVI Pro HP Tuners suite for another project and decided to license my truck out of curiosity. Seems the whole problem with not staying locked up on the shift is EFI related. Commanding it to stay locked with HP is a solution, at least for me. All shift commands seem to "do as they're told", and my annoying 3 shifts for one going into 4th is gone. I will also add that I like the HP method of tuning the PE table as well, much easier and clearer for the new user to make it cooperate....