4L80E 4-2 downshift??
02-21-2013 | 12:48 PM
#11
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11 Second Hall Moniter
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From: Wyoming
Alright guys, thanks for confirming what I already suspected.
The transmission is fresh & has a shift kit. It downshifts quickly & firm. He is just used to his old 60E, and the way this one acts was different and he was alarmed. Asked me if I could change it. I didn't want to be wrong when I told him it was normal.
The transmission is fresh & has a shift kit. It downshifts quickly & firm. He is just used to his old 60E, and the way this one acts was different and he was alarmed. Asked me if I could change it. I didn't want to be wrong when I told him it was normal.
02-21-2013 | 01:30 PM
#13
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11 Second Hall Moniter
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From: Wyoming
Sounds like an issue with the shift tables. What changes from stock did you make?
Lots of changes, trans is built & has shift kit and a Pro Yank.
Did you only adjust WOT shift speeds/RPMs or the partial as well?
I made several adjustments to all of the tables, and it still acted the same.
Also have you logged the truck while doing this? What does the TPS% look like during these shifts?
Yes, the datalog shows the PCM commanding the shifts in this manner. TPS at 100%.
Is this a DBC or DBW truck? Also what does your TPS enable full throttle % look like?
It's an early DBC (GMC C3). Full throttle enable at 85%. Tried lowering it just for ***** & giggles, didn't change anything.
Something seems very odd here.
Looks like it's normal actually.
Lots of changes, trans is built & has shift kit and a Pro Yank.
Did you only adjust WOT shift speeds/RPMs or the partial as well?
I made several adjustments to all of the tables, and it still acted the same.
Also have you logged the truck while doing this? What does the TPS% look like during these shifts?
Yes, the datalog shows the PCM commanding the shifts in this manner. TPS at 100%.
Is this a DBC or DBW truck? Also what does your TPS enable full throttle % look like?
It's an early DBC (GMC C3). Full throttle enable at 85%. Tried lowering it just for ***** & giggles, didn't change anything.
Something seems very odd here.
Looks like it's normal actually.
I didn't want to ignore your post, so I answered your questions above, in red.
02-21-2013 | 05:26 PM
#16
Interesting... something to look out for/be prepped for when i do my swap. Does this also happen on the 3-1 shift? Or the 4-1 shift? With the tight ratios of the 80e I would imagine a 4-1 shift isnt that uncommon with a heavy foot.
02-21-2013 | 07:44 PM
#19
that would be a real bummer if there is no skip shift... doesnt really sound right to me. I feel like it would have come up before.
02-21-2013 | 07:49 PM
#20
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11 Second Hall Moniter
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From: Wyoming
Why don't you datalog yours, and see if the trans commands 3rd before it commands second, and report back?