Abnormally long time for overdrive to kick in? Possible trans issue

Hoping someone can point me in the right direction here. 2015 4.6L w/ 165k miles.


Driving out of town for work yesterday approximately 90 miles away. Crappy weather, downpour most of the time. Everything going as it should until I start to head home. I take a corner on a fresh wet road - felt my truck slip a bit and then correct - didn't notice the traction light ever come on though which I thought was odd. After I get up to highway speed I notice a loud drone and glance at my RPM and noticed overdrive wasn't kicking on.

Cruising at 50 - 3k rpm
Cruising at 60 - 3.5k rpm
Crusing at 70 - 4k rpm.

First thought was turn truck on and off but didn't want to risk not making it home. Went 40 mph almost the whole way home until I turned onto the last stretch of highway. As soon as I turned onto that road, the truck went back to normal and overdrive started working again. Cruised 70mph the rest of the way and never got above 2k rpm. Got home and turned truck off for an hour then drove it around town for 20 minutes and to work this morning and everything is back to normal..


Is my transmission about to take a dump or is there a sensor somewhere that may be faulty?

 

Prob just a shift solenoid being sticky. I'd have it scanned for any intermittent codes that aren't triggering the CEL.

 

Could also be low on fluid... when's the last time you had fluid replaced?

 

I've never actually had anything done with the transmission. Was told it was sealed and didn't need to be serviced but after reading up some on here I think I may do a drain and fill.

 

That will be the best $180 ($?) you'll spend on this... if you tow a lot or are loaded or wrapped or on RPM often, I've heard every 30k+ miles is good for drain-refill....but that seems excessive in most cases...every 50k+ is good insurance tho... I've done mine twice in 40k and it's been dirty AF both times, tho the second time was less than first... truck shifts great and correct when warmed up!

 

May be a performance D solenoid starting to stick. This is a SWAG (swinging wild ass guess) though. I would suggest first drain and fill, it takes about 14 quarts, but 4 quarts at a time every 1,000 miles or so can help get most of the old fluid out.
I also fell for the sealed transmission gimmick, until I read some of the Tundra's work book from the factory if you get certain codes, try changing the fluid. This is cheap insurance as long as you stay on top of your fluid changes, some say 30K miles per change, but if you haven't done it start with the 1,000 mile interval first, then move up to the 30K miles.