I have a Banks exh. brake & the TC lockup drops out below 1500rpm. I think it's because the line press. is too low then to be effective at the TC?
The line pressure should be fine at that RPM. It would make more sense that they feel the retard torque would not be high enough.
If you don't mind another query; My rebuilt 48RE was done to handle my RV towing needs & has worked fine for a year. Lately I'm seeing some numbers on my Trans Slip display [Banks Automind Tuner w/PDA]. My shop reports not seeing anything RPM related to support that PDA display. The transmission was dropped & stator pump assy checked for leaks, and a new Precision Triple Disc TC was installed as well. Got a clean bill of health.
On interstate few days ago @ 65mph & slowly floored it, backing off @ 115mph. The Trans Slip display showed up to "20" [RPM slip]. An acquaintance said WOT unloads the TC lockup. Sound right to you? Whilst hauling up a grade & I decide to use full throttle [in Tow Haul], will the TC then unlock?
On a 4xRE I do not see how they would calculate the TC slip. You would know only the input RPM (engine RPM) and output shaft speed. Without having a sensor on the input shaft of the transmission (driven by output of TC) they can only calculate the slip if the gear ratio is known. I suppose they could do that, but I'm not sure how with no other speed sensors. Any calculated slip would include the TC as well as the applied element. The TC will generally unlock on WOT with stock programming.
My current setup is calibrated to Lockup above 50mph & dropout below 45mph. Is this reasonable for towing. Should I consider maintaining Lockup <45mph?
As long as you have the torque available for the load you are towing there isn't a good reason I can think of to not be able to set it lower.