5th gear lockup at WOT issue

2020 HP 70 transmission, relatively new 3rd gen with stock 392 converter, struggles big time to lockup in 5th at WOT, and I am wondering if anyone has experience at using TCC pressure-apply tables and can provide a possible solution.
Notice the rpms do not vary, but the MPH increases after the 4-5 shift (shown) when the converter is called for indicating the clutch(s) is/are laboring when trying to apply. I prefer it to be decisive or I just won't lock it until 6th after I get out of it. I don't exactly know which tables to manipulate without guessing, so I would appreciate hearing from those experieced with the converters
Thank you.

Attachment 160697

that is clutch slip steve - has nothing to do with the converter

clutch pack in drum C is excessively worn, or the tune is wack.

once trans is in 4th gear and nothing is slipping, the only thing that changes when shifting to 5th is -

1) the TCM removes current from drum C solenoid...

2) and it applies current to drum E solenoid.

what messes a lot of people up is that the solenoids for drums C D and E are all normally open

A and B work more like brakes in that trans and the solenoids for those two are normally closed.

without understanding that it would be hard to tune the trans



you can test my "that is clutch slip - has nothing to do with the converter" statement by unlocking the converter and making another log

You can't be serious, what are you high on ? Just kidding. This trans shifts like a rock all the way through to 6th (without using the lockup after 5th) in 200 to 400ms

Here is one when the converter clutch appears to takes hold after a time and the rpms start to climb. I have used lockups in the past on other application and they would take hold decisively. This is the last time I will try locking this one at wot until I learn more. I got out of it right after.

Attachment 160706

its not that

recovery rpm is well above stall

tire spin or clutch slip

is it blowing the tire off at 100 mph?

The car runs like a scalded dog. The transmission is near brand new and there is nothing wrong with it. It shifts 6th gear just like the rest in 200 and some ms if I don't use the lock, I mentioned that once....You are just not comprehending evidently, and that's ok. No big deal. Let's just forget it

more contempt prior to investigation.

apparently its contagious...

Quote:

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Originally Posted by Joe Tcat

You are just not comprehending

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dont just say this IS what it is doing...

show us:

lay the crankshaft rpm

over the input shaft rpm (turbine speed)

over the driveshaft rpm (output shaft)


might wanna throw wheel speeds in there too just for good measure : )

Quote:

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Originally Posted by Joe Tcat

2020 HP 70 transmission, relatively new 3rd gen with stock 392 converter, struggles big time to lockup in 5th at WOT, and I am wondering if anyone has experience at using TCC pressure-apply tables and can provide a possible solution.
Notice the rpms do not vary, but the MPH increases after the 4-5 shift (shown) when the converter is called for indicating the clutch(s) is/are laboring when trying to apply. I prefer it to be decisive or I just won't lock it until 6th after I get out of it. I don't exactly know which tables to manipulate without guessing, so I would appreciate hearing from those experieced with the converters
Thank you.

Attachment 160697

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By factory, torque converter has "limits" to close the torque converter. These limits are basically rpm and torque.

Depending on how you would like to command the closing, system will "struggle" to do it.

Question: Did you try closing torque converter earlier (maybe third, second, or even first) to see if you have the same issue?
If answer is yes and torque converter is not closing properly, it is either tune or hardware issue.

If you need more support, share a log and a tune

contact support and have them add:

[TCM] 46947 - TCC Pressure Offset For Lock

currently your tune does not include this table.



*and post a log with the channels i mentioned ^^^ added : )

press offset for lock