transmission acting strange

[Beermoney]

my 2001 qx4 started to not respond to the tow-haul switch on the shifter. about the same time the torque converter started unlocking for no reason. now it will sometimes down shift at highway speeds on flat roads. other than that it shifts very good.i am thinking some sensor somewhere. any ideas, anyone.

[mdmellott]

my 2001 qx4 started to not respond to the tow-haul switch on the shifter. about the same time the torque converter started unlocking for no reason.

Are you referring to the O/D Off switch? When you say "torque converter started unlocking", are you saying it completely frees up like it's in neutral?

[Beermoney]

yes overdrive switch and no not in neutral but unlocked.

[mdmellott]

If your ATF level is good and there are no DTC codes being flagged, I have no idea where to even start with diagnostics for this.

[Beermoney]

anybody

[VStar650CL]

If there are no DTC's then it sounds like a bum Torque Converter clutch. I doubt it's electrical, a weak coil would be diagnosed by the TCM. If you can get a scanner with work support that lets you manipulate the TC clutch solenoid, switching it on in gear at idle should instantly stall the engine. If it doesn't then either the solenoid is mechanically leaky or the TC clutch is bad or slipping.