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?

 

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?

 

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.

 

Is this in D or manual 1st/2nd?

 

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."

 

Theres a chance it could just be linkage not correctly lined up, but its likely internal to the trans.

 

Pan removed and re-installed...no carnage found.
Solenoids are clicking when shifts are commanded as well.
Scratching my head now...or chin

 

i could not manually put my truck in 1 untill i switched shifter cable brackets, the one i was using was messing with it

 

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?

 

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.