08 LS460 Transmission Hesitation to shift

[Flight_Engineer503]

Ok so Ive searched and have found many inconclusive threads on this topic, my 08 with 115k will routinely clunk into either an upshift or downshift and even reverse (R will display on the dash, but the gear has not been physically engaged in the transmission). The vehicle is very well maintained and I am the second owner. Recent maintenance includes complete front suspension bushing replacement, 4 hubs, 4 brakes, TRANSMISSION OIL and FILTER REPLACEMENT with Toyota WS fluid, WP, Thermostat and radiator hoses. All this done as preventative maintenance. 

 I notice that the hesitation and rough shifting tend to be more prevalent after the car has been on the road for greater than 20 miles, however, it does tend to hesitate upshifting after a fresh cold and dark startup (then subside for a while). I also observed that if I momentarily lift off the throttle then immediately back on the throttle, the car will upshift quicker. 

 What Ive seen in other threads, there are TSB for cylinder heads and other things such as computer updates, but that just seems to be throwing all the parts at the vehicle to fix a root cause. Has anyone actually found what causes this annoying issue to occur? Other than this problem, the car did tend to get pretty hot with the AC running in traffic in the 110+ Texas heat this summer, but that is a non-issue at the moment. I love this car, but this annoying problem is about to make me sell it.

Edit: Im going to be taking this car up to the dealership one of these saturdays in the next couple weeks to have them hook up the computer for a possible firmware update, will report back on the results. Service was quoted at $140.

[RX400h]

Did this happen immediately after the transmission fluid/filter maintenance?

Here's a good read:

 

[Flight_Engineer503]

31 minutes ago, RX400h said:

Did this happen immediately after the transmission fluid/filter maintenance?

Here's a good read:

 

It happened a bit before that but that seems to have exacerbated the problem