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TRANS GURUS: Manual shift vs ECU commanded shift

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Old 04-28-2014, 01:04 PM
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Default TRANS GURUS: 4L80e - Manual shift vs ECU commanded shift

This may be a stupid question but I am fairly close to being transmission illiterate.
(Original 4L60e cable / bracket / linkage being used on current 4L80e)
IF there were a cable / bracket / linkage binding issue that prevented trans from going into 1st gear
WOULD a commanded 1st gear be affected as well?

Last edited by Superado; 05-14-2014 at 05:04 PM. Reason: added info
Old 04-28-2014, 01:22 PM
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Also...on a fresh rebuild...if a commanded 1st gear just binds up and loads engine until you command 2nd...then it frees up...what could that be?
Something as simple as a shift solenoid or something catastrophic?
Old 04-28-2014, 01:27 PM
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If you are attempting to put it into manual 1st but it can't quite get there so it's actually in manual 2nd, then I believe it will not use 1st gear since manual 2nd should prevent 1st gear. But 1st should still work in D.
Old 04-28-2014, 01:31 PM
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Originally Posted by Superado
Also...on a fresh rebuild...if a commanded 1st gear just binds up and loads engine until you command 2nd...then it frees up...what could that be?
Something as simple as a shift solenoid or something catastrophic?
Is this in D or manual 1st/2nd?
Old 04-28-2014, 01:37 PM
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In D as far as a I know.
My tuner is telling me that 1st is not working when he commands it from D while on the dyno.
He said, "it binds up and loads engine...when you put it in 2nd, it frees up."
He said that you can manually put it in 1st and it basically does the same thing.
He said the last time he saw this that he found "roller sprag and drum was shattered."

Last edited by Superado; 05-14-2014 at 02:48 PM.
Old 04-28-2014, 09:21 PM
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Theres a chance it could just be linkage not correctly lined up, but its likely internal to the trans.
Old 05-14-2014, 02:56 PM
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Pan removed and re-installed...no carnage found.
Solenoids are clicking when shifts are commanded as well.
Scratching my head now...or chin


Last edited by Superado; 05-14-2014 at 03:10 PM.
Old 05-14-2014, 03:03 PM
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i could not manually put my truck in 1 untill i switched shifter cable brackets, the one i was using was messing with it
Old 05-15-2014, 09:53 AM
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If the tranny has had the vac modulator mod since day one w/o issues...which it has...
is there anything in a standard rebuild that could cause issues if this mod isn't taken into consideration when rebuilding the tranny?
Old 06-13-2014, 10:40 AM
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Solenoids checked and seem to be fine.
Valve body checked and seems to be fine.
Truck will not shift out of 2nd automatically at all.
Both SOLUS and efiLive can command 2nd and up...but still not 1st.
No metal in pan.


Last edited by Superado; 06-13-2014 at 01:09 PM.


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