Difficult Auto Trans Shifting... 2013 Tacoma V6 5 Speed Auto

2013 Gen 2 , Double Cab, V6, 5 Speed Auto Transmission with Towing Package ( Factory Transmission Cooler Installed).

I'm the original owner & the only driver.
So my Tacoma is 8 years old with 75,000 km.
No Special Operating Conditions ( no Towing Trailer etc)
No Dusty Muddy Off Road 4x4 Operation (just exercising controls).
(I didn't need a 4x4 but Pre-Runners cannot be imported to Canada, at least back in 2013.)

OEM Owners Manual Supplements Required Maintenance schedule ends at 200,000 km, 12.5 years). Transmission Service is not mention for normal operation. I was going to maybe do it at 150,000 km & but i'm only at 75,000km.

I doubt if i would go for the Flush. I'd go Pan off , with the cavities like Filter & Torque Converter that hold Fluid being removed.
I want to make sure replacement is 100% Synthetic ATF WS.

I remember when i bought the Tacoma asking the Dealership Senior Toyota Mechanic about no Auto Transmission Service Schedule & he said Auto Transmission is a Sealed Unit and leaves Factory with Synthetic Fluid so if there are is no Towing of trailers , the Transmission Fluid is good out past 200,000 km.

Last year, the Auto Trans Shifting Lever became stiff. I went under and spayed it with some Tri-Flo Lubricant and exercised the Shift lever and it seemed to solve the problem. Spraying the Connection where the Cable Connects to the Operating Lever on the Transmission Housing.

So now it's pretty cold here, and it's happening again. I went under and made sure there was no snow or ice causing the Problem. All Clear of anything that could be blocking Transmission Lever moving. No Cable Kinking.
Spayed it again & excised the Shifter. Maybe a little difference...not sure.
Problem not Solved.

Went up top in Cab and removed the Plastic around the Transmission Lever and everything nice and clean ....free of critter nests etc.

Next step is to take it to a Shop put it on a Hoist and have the Cable Connection to the Transmission removed . Test the Shifting is easy with cable disconnected. I expect this will be the case...confirming the Cable is not the problem.
(( as a side Note the Replacement Cable Toyota P/N: 3382004010, is not available in Western Canada... supply chain problems and even RockAuto doesn't show the Cable assembly.))

I'm hoping that removing the Cable where it's attached to the Transmission Housing Operation Lever is the Problem , it looks pretty cruddy. Maybe properly Cleaning it up will solve the Problem.

What are the chances my Problem could be related to Auto Transmission Fluid. I'm pretty sure it would not be from Contamination. Why would dirty Transmission Fluid cause hard Shifting?

What about Low Fluid Level ? Could the Fluid Level go below the Operating Arm level be the Cause ?

I read in some posts sometimes transmissions leave the factory with low Levels and with no Dipstick...who's to know.

Any Insight would be much appreciated. No heated Shop so Worst time of year to have a Vehicle problem.

 

From what are you saying, the problem looks like external.

 

My 2014 4Runner would do that in the freezing winter. It was a bad neutral safety switch. Apparently it was a factory defect and the switch would get moisture inside. When it froze said moisture would freeze and make the gear shift level hard to move.

 

^^^ This. Had the exact same issue on my 2014 and lubricating the switch (located on the passenger side of the transmission) helped the issue. Replacing the switch completely resolved the issue. The new switch then got liberally coated with Fluid Film to prevent the problem from happening again.