Transmission flush

Take cooler lines off and run hoses? Missed a window? It's basically a drain and fill and you just monitor the temps before you set the level. The hardest part you have already done with the drain and fill. Setting the level is simple.

 

I'll admit, I'm a Amsoil fanboy. I don't know why. My first "newish" vehicle was a 2005 Nissan Xterra that I purchased in 2007. On the Nissan forum I frequented everyone preached about Amsoil so I ran it because I'm a lemming that enjoys following. I then bought a new Nissan Frontier, swapped it all to Amsoil basically as soon as I got it home. I drove that truck for 6 years and the only thing it ever needed was new brake discs and pads, the factory ones lasted 65,000KM. I've just found that I haven't had any issues since running amsoil. That being said I haven't had any issues running anything else either. I guess since I trust it, it's not broken, I'll keep using it. I already purchased the amsoil transmission fluid, a lot of it, so I'm going to drain/fill until the stuff coming out looks new.

 

amsoil is good stuff, no doubt

 

So transmission has mostly fresh fluid in it now. Used Amsoil, drain and filled about 16qt total.

I’m Canadian so I don’t know how many washing machines are in a quart or donkeys make up a mile so I’m switching to metric.

truck has 70,000km on it, first drain and fill for the transmission. Of thw 70,000KM at least 30,000 are towing a 16’ enclosed, steal frame trailer… pretty loaded up.

step 1. I changed the rear differential fluid. As recommended by posters on this thread. The truck had already had the differential fluid changed early on with Amsoil 75-90 severe gear oil. I wasn’t able to get Amsoil today and wanted it done so I used Lucas full synthetic 75-90. Old diff fluid was a little grey but not bad. I’d guess between 1/32 and 1/16th of an inch of material on the magnet. Worry free now that it’s done

step 2 drained the transmission. Almost 4L came out of the pan. Put the same amount back in the pan, ran it for 5 minutes, shifting through gears. R-D- S1, S2 and up. Did this 4 times. So about 16L out and 16L in. Each time I refilled I put slightly more back as the new fluid was room temp and the transmission was warm to hot.

Step 3. With the engine running and transmission at temp using a scan gauge, I then set the fluid level at the proper amount using the Toyota technique with the check plug.

Here are some photos of the first drain vs the last drain. I’m planning to repeat MAYBE, next month. Maybe.

 

Been a couple months and I decided to do a drain and fill again today, just to see how the Amsoil looked after a winter of driving and hauling. Again %90 that this truck drives it’s pulling a fully loaded 16’ enclosed trailer.

Still looks new - as it should.

 

Did u do check fluid level at proper temp?

 

Yes

 

oops sorry missed that post. Looks good

 

Have you installed a transmission cooler on your truck?

 

As far as I know the 2021 Tundra, with tow package, came with a supplemental engine oil and transmission cooler? Mine came with the tow package.
https://www.oxmoortoyota.com/blog/t...n enhance,oil cooler and transmission cooler.

 

Ehhhh it's not really a cooler. It is according to Toyota, but really isn't just a engine coolant bypass/heat exchanger that is designed to help warm the ATF, then attempt to keep the ATF cool once it's at operating temp. But it does not have an integrated, or dedicated, fin style cooler like you might assume. Toyota did away with that in 2019.

If you want to add one to your truck you can buy buying this: https://www.tundras.com/threads/5-7l-transmission-cooler-kits.60550/ or build one yourself. But it looks like you are taking really good care of your truck anyway while towing a lot! So if you're not seeing abnormal temps while towing, and running good fluid, you'll probably be just fine without one.

 

This. There has to be thousands of people that are towing all kinds of things without any knowledge that the cooler was removed and we haven’t heard of any widespread transmission failures. Regular maintenance definitely plays a big part in keeping these transmissions going

 

Absolutely. It seems like 19-21 owners ever see issues when they don't take care while towing. i.e. bombing up hills with the torque converter not locked up, or reversing up a big hill with a heavy load.

I still like that my 2016 has a proper cooler, but I also watch the temps like a hawk while towing. Paying attention and proper maintenance go a long way!

 

I think if I was worried about heat I’d get one and install it. My previous truck had a heat exchanger for the transmission that ran through the radiator, warming the transmission when cool and somewhat cooling it when hot. The big flaw with this was the transmission heat exchanger would corrode and eventually coolant would end up in your transmission… destroying it.

I live in the great white north eh? And where I live we only have maybe 4 weeks a year where the outside temp is 30C or warmer (87F) and we really don’t get days hotter than 95F unless there is some weird heat wave. If we had hotter outside air temps for longer I’d be considering an external rad cooler on a fan but for now I think I’ll stick to a transmission drain and fill annually.

 

Yeah you'll be just fine. The 07-18 Tundras have what you describe where the cooler is integrated into the radiator. Luckily failure with those seems to be extremely rare on Toyotas, but yeah, I don't love the design either. If I ever replace my radiator I'm just going to install a dedicated external cooler to eliminate that potential failure point.

 

So actually that's a bit inaccurate. At one point it was a standalone auxiliary cooler, not integrated to anything. Then at some point it became integrated into the AC condenser.

 

Correct.

If someone is concerned about about transmission oil contamination through the rad, it won't happen from the radiator but from the heat exchanger on the transmission. That would be extremely rare.

 

Been reading up on this procedure and will be doing it this weekend. I have the fluids. Question. I haven’t seen anything on gaskets for the bolts. Not talking pan gasket (not doing that). Are there gaskets on the drain, fill and overflow bolts?

 

Yes there are gaskets on the bolts you mentioned. The only one I would be changing is the drain bolt washer.

 

I found one post. Is the part number

$8 35178-30010 luxlead 20 PCS Transmission Drain Plug Gaskets Oil Crush Washer Seal Rings Compatible with Toyota Lexus 4Runner Sequoia Tacoma Tundra Lexus GS450H, IS250/350, LS430, LS460, Replaces 35178-30010

35178-30010? Assume this fits the 2.5 gen.

 

I've done six drain and fills and never replaced anything besides the fluid, no issues.

 

Go to a Toyota parts online site and verify the the part number. I don't want to steer you wrong.

 

The fill bolt has an O ring rubber gasket, I replaced it as it’s only a few cents from the dealer. Drain plug is a copper washer. Again I got this from the dealer. I bought all the o rings, washers and the pan gasket because I was planning to drop the pan and replace the filter/clean the pan. The more I read about that the more I realized I was going to break a pan bolt and didn’t want to spend a day drilling out broken bolts on my back in my garage.

 

You are 100% correct! Thank you for clearing that up. Clearly I was wrong and was thinking of how my GM still is. Having it integrated with the AC condenser is at least a bit better.

 

Sure thing. I'm a little worried about some reports that on the 2018's the AC suffers because of a transition to a less efficient refrigerant (I'm sure in the name of saving the walruses). Supposedly that new refrigerant struggles to overcome the heat exchanged by the transmission on hot days. I just bought my 2018 in December, so have yet to need the AC yet, but it gets pretty warm down here in AZ.

 

The 2019 to 2021 use the new R1234YF and looses the transmission cooler. There is no heat exchange between the AC and transmission. The R1234YF Tundras use a stand along condenser. The T1234YF refrigerant is less efficient at exchanging heat so the condenser is larger then on previous models which used R134. Toyota could not use the AC/transmission heat exchanger because of the new refrigerant so they simply dropped it and relied on the warmer/cooler heat exchanger mounted on the transmission. Because the new Tundra was coming out Toyota decided to simply just remove the transmission cooler rather than redesign to save money.

 

So is everyone saying that 2019-2021's have no cooler mistaken, and it's actually 2018-2021?

 

Open your hood and look at the sticker that shows your refrigerant type. If you have R-1234YF you do not have the ambient transmission cooler.

Your 2018 should have R134A so it should have the cooler. I've made the year correction in my post.

 

R-1234yf

 

Wow, a 2018 using R1234yf. Then unfortunately you don't have a ambient transmission cooler. What is your production date, month and year, on the door sill?