4.9 with e4od

i have code 628,

tc was replaced and code reset but still there,

any ideas.

also how does the computer know it’s slipping, I’m sure it looks and the speed sensor but what does it compare it to on the engine to know

bonus question, when I turn my key over the tach go straight to 3000, I tried 2 other tachs and all did the same, what could cause that

 

Are you still getting that as an active fault or is it a stored code? It could be either.


You needed a tachometer to realize it was running that fast? Does the idle come back down to normal or does it stay that high?

 

Nah, even with the truck off it reads 3000 when they key is put in run.
I cleared the codes,
could a clogged vent cause that

update just did a pressure test and it runs between 80-90psi in all gear selections