Re: Overdrive & engine rpm question
In the 63-65 mph range you're right near the stock shiftpoint from 4th to 5th, and both are overdrive gears. With stock size tires, if you're in 4th, you'll be ~2200 RPM, and 5th you'll be ~1900 RPM. For me, living in hilly terrain, it's just about perfect if I drive at 63-64 mph. On level ground I goose it a little and it shifts to 5th. On inclines I backshift it to 4th and then back to Drive. This allows maximum use of the MDS, as many times on slight inclines the MDS will be off if in 5th, but will come on if in 4th (Drive). Also, be aware that with MDS active it will add ~50-125 RPM. When it comes out of MDS the engine RPM drops the same ~50-125 RPM to match turbine speed, if locked. The converter lock also plays a part here. It is not on when in MDS mode, but will come on, sometimes simultaneously, when the MDS kicks off. Bottom line, in this speed range, you should notice quite a bit of RPM shifts (could be mistaken for "hunting"), depending on the amount of hilly terrain, wind, etc., and yes, even type of road surface. I've seen up to about 4% change in engine load when changing from one type of road surface to another....i.e asphalt to concrete, or vice versa. This will also affect the MDS, which is load sensitive, among other parameters.
05 LX/RT and 06 WK/GCO, (modded similarly) with MDS "ON" Light, Vortex Gens, Debadged, DashHawk, BT Catch Can, SRT CAI W/Add Air Inlet, K&N Filter, Sonnax Trans Line Press Booster, SC Tuner W/Adv Trans Tuning App, DS Tuner, Cust tubular headers w/3 in. catback, Bilsteins, SRT frt/rear bumpers, Eibach SRT Lwr Sprgs & Sways, FRI Sidewinder Cam Adv 2*, 6.1 valvetrain, SLP 25% UD Pulley, BBK 90mm TB, SOS Coils/.060 spark plug gap.