transmission fluid

Got my truck with 65k miles preowned dealer said they replace all fluids which I asume tranny too, even the seats were new so Im at 143k this morning notice while on the highway tranny did not shift from 3rd gear to 4th had to stop and move the shifter from D to L back to D and drive again and is working as normal ....I think time for an fluid change is needed dam!

Its been almost 100 degrees here Mass for the last 3 days could this be the reason?

 

Don’t ever assume anything, especially coming from a used car salesmen.

 

The problem with changing tranny fluid on high mileage vehicles is because the old fluid gets burned to the clutches and gears in the trans. The new fluid has detergent in it too clean the trans. So when you flush it out and then add the new fluid, you can damage your trans because the detergent gets rid of the deposits left over and that's what causes the slipping. You don't find a shop to do a trans service on vehicles over 70k without a signed waiver. I was a fluid tech for years and we told customers to do a drain and fill or leave it alone after 70k on automatic trans.

 

It’s only an issue if the old fluid is burnt. Old fluid that’s not burnt isn’t an issue.

 

Here’s what mine looked like vs new fluid after 120,000 miles. I did a full flush with new filter and it shifts great with no problems. You may as well flush your power steering fluid as well. Valvoline MaxLife synthetic ATF is great for both!

 

The only way to find out for sure whether to flush or not is to take out an ATF sample and get it analyzed. But yes, very high mileage ATF may contain metallic specks that will cause a transmission to slip when those specks are removed. Burnt fluid can usually be flushed out if the fluid is not contaminated with clutch material or metal specks.

Chris Fix explains some of this:
https://www.youtube.com/watch?v=o690DovjDAc

 

now I’m trying to debate whether to even touch mine at 70k . Pretty sure it’s never been flushed. I may just get 6qts. And flush 3 quarts through it a couple times.

 

70k is barely broke in.

 

I agree with the OP saying that "they don't know shit"...My 09 has an auto trans with the 2.7 engine. One dealership told me it is a sealed tranny and I don't have to touch the fluid..ever! Another service advisor said it was a sealed tranny but I should flush it...The owners manual says nothing about my transmission except for how to use it..I had an inde shop that works on Toyotas and they did a drain and fill at 50K...Showed me the dipstick and on it it said type 4, fluid,,It also said never to change the fluid on the dipstick.Oh...also went to a third service department and they said it's sealed and never change it...Bottom line...I will drain and fill every 30K and check the trans fluid using the dipstick...There was no mention in the manual of a dipstick...Very confusing !

 

When the dealership tells you it's a sealed transmission, they really mean come back to us when your transmission breaks down and we'll sell you a brand new Toyota with 72 month financing at 6.35% APR.

 

My routine for 2014 Tacoma (WS), 2012 RAV4 (WS), and 2012 CIVIC (DW1 fluid): Drain and fill every 30K. Super easy and gives me piece of mind. I will re-evaluate at 100K. All listed are below 80K now.

 

There’s so many different trains of thought on this.

 

So what’s the proper way to do this? Just drain out 3 quarts and put new fluid in?

 

Are you referring to the 2018 truck in your sig or do you have a 2nd gen truck as well?

 

This is a Gen 2 thread and there are some very good instructions...
https://www.tacomaworld.com/threads/how-to-drain-refill-automatic-transmission.63851/

If your in a 2018 per your info, might want to check the Gen 3 forums.
Here is a Gen 3 general maintenance: https://www.tacomaworld.com/threads/3rd-gen-diy-maintenance-quick-reference.406712/

Just checked... look half way down in that link for Gen 3... how to

 

To my knowledge, most, if not all, maintenance manuals say to flush the ATF (from 40k-60k) when your driving falls under special/severe operating conditions - offroading, commercial use, towing, etc …. My Taco and Lexus manuals say to flush every 60k under one of these conditions.