6 speed not updating current gear fast enough
- Thread starter Js95gt
- Start date
Or check the seals on the pressure manifold switch. That is what tells the TCM that the valve body has setup for the next shift.
Is it looking for pressure switch feedback, or gear ratio calculation?
Trans shifts too good to have any type of clutch issue.
Trans shifts too good to have any type of clutch issue.
It uses gear ratio calculation to tell it if it has shifted, it uses pressure switch feedback to tell it when the shift valves have changed and set up for the next shift.
That's good info. I'll try to catch a log of PSM inputs and calculated gear ratio and see which is lagging behind.
My old trans used to blow past shift points bad. Like stock shift points and would see 4,600rpm in logs. Not the case with the trans built by Evan. Shifts where it is supposed to. Clutches were gone and tolerances weren't right in others.
This can happen as well. It can only apply the clutches so fast, so ifthe tolerances get to great, it has to spend to much time applying clutches, releasing, and waiting for the TCM to see it happen. One of these days I need to scan in a copy of the shift charts from the priciples of operation manual so people will see just how much goes into each and every shift so they can understand why the ALLISON behaves as it does.