Fantastic write-up 46runner! Detailed pics and instructions will help many others. Thanks.

These guys below said or hinted at an optional way that might be easier and quicker too... ??????


I am a T4R newb, but do you have to have the tow package in order to do what you said? My friends 2005 does not have the tow package (that I know of) and the trans cooler lines attach to the side of the radiator; trans cooler built into the radiator. So I can do exactly what you said (without tow pkg) right?


My thoughts exactly. Why can we not interrupt the loop at the cooler; one hose goes into a large empty catch can, while the other hose is dropped into a bucket of brand new trans fluid... ? One raw hose is connected onto the cooler output, and the trans cooler return hose on the truck would have to be extended using some raw tubing in order to do this.

Each bucket would be tick-marked to allow you to see exactly how much fluid comes out -verses- how much goes in. Once engine is turned on, the trans fluid pump should do all the work for us. The trans pump should just suck-it right up. Optionally; we could use a huge (home-made?) funnel for the new fluid, allowing gravity to help on the suction side...

If lucky, after running engine for about 3 minutes, the 2 buckets would have used the same amount of fluid. IF unlucky, you would have to interrupt it or manually adjust it accordingly.

No matter how lucky or unlucky with this method, I would fully expect to make a fluid level adjustment via the overflow plug as a final check.

The transmission will not suck fluid back in. I just used a funel and attached directly to the return line and poured in. Its not an exactly even exchange, but you eye ball it and you will get very close then pull check plug and add or let extra pour out. Bring to temp and recheck. I had a friend help with starting and stopping engine and start to finish was only 45 minutes. next time I do it it will probably take half as long.

You never know till ya try. There is a pump inside the trans, right? It might just work; especially if the test lines are primed (no air inside). If not, we go back to my other thought...

"Optionally; we could use a huge (home-made?) funnel for the new fluid, allowing gravity to help on the suction side..."

Using the gravity/funnel sounds better tho.

I am planing on doing this job on my friends 4R. I will hopefully get back here and post my results.

Cheers!

I did try otherwise i would not make such a statement. The pump is on the supply side. When you tap into the lines you get the pump pumping fluid out, but since the loop is interrupted there is nothing mechanical to bring the fluid back thus a funnel and gravity. The flow back into the tranny is almost the same rate as pumping out.

Thanks for the added info Gatafly.

The OP showed the inlet and outlet hose location on the trans. Here is that pic:




When I get around to doing this job, I will likely be disconnecting one or both of these hoses at the radiator/trans cooler. Does anyone remember which hoses is which?

Trans fluid hose on the Top side of radiator = green -oil cooler outlet
-or-
Trans fluid hose on the Top side of radiator = red -oil cooler inlet

Logically (to me) seems like the red-oil cooler inlet should be the Top hose on the radiator/cooler... and the bottom one (on the radiator) would be the green -oil cooler outlet.

I can and will trace the lines from the trans to the cooler in order to answer this question, but thought I would ask the question anyway because the 4R is not here, not mine, and only see the 4R occasionally.

Thank you.

Just did this on my GX(essentially 4Runner with a tow pkg) and the top (green) line is the top side of the radiator. The fluid pumped from the transmission came out of the rubber hose that attaches to the radiator. It did not come out of the radiator. Hope this makes sense and helps.

I did not disconnect the red line to refill and instead refilled through the fill plug hole.

All in all, I flushed 11 quarts and refilled the trans with 12 to make sure there was some coming out during the fluid temp check.

Some more notes:
- Initial drain was 3.25 quarts
- At 69k miles, fluid looked like used black motor oil. Actually thought for a sec I pulled the plug.
- Flushed 2 quarts at a time. I did a long 10ish count for each quart.
- I had access to a lift and snap-on scangauge/techstream so I could pull the actual trans temp in real time (no jumping wires in the OBD port)

- After my 11 quart flush/12 quart fill, initial trans temp was 93. ATF I used was room temp. Ambient temp was about 70.
-I did drive about 30 miles prior to starting and waiting about 3 hours.

- During the temp/fluid check, the overfill fluid was brand new, bright red. Therefore, you can successfully replace all your fluid with 11 quarts.
- During two of my two quart flushes, I cycled through all the gears. It was quick but doable.
- I used Amsoil Signature Series Fuel-Efficient ATF which is what they recommend for WS replacement. Post flush 40 mile drive was uneventful. Seems smoother and quieter but might just be placebo. I'll be running this fluid for at least 50k miles.

Only comment I have add is if you have the tow package you can pull the trans-cooler lines in front of your radiator which is much easier than accessing lines from underneath.

can a scangauge II be used to check trans temp for this flush? i have the trans temp code loaded.

also, how do i get the best deal on the amsoil fluid for this flush? from a dealer or just sign up myself?

Thanks guys!

Regarding your question above, see this thread on the additional transmission cooler installed on some 4runners: Advice-Drop the Pan or Dealer Flush?
I'm just calling it a tow package as I have the additional cooler in addition to a different receiver hitch setup/mount.

For the sake of repeating and clarifying what you said....

Trans fluid enters the radiator on the bottom-line and the fluid exits at the top-line. Correct?

I read that thread at link (plus others too). Thank you.

Some people said tow package includes external cooler, while others said it does not. I do not need to ask or re-hash that subject. My friends 4R does not have an added or an external cooler but does have a trans fluid cooler built into the radiator. The trans fluid cooler connection lines are on the drivers-side of the radiator. I'm good. Thanks.

I'm not familiar with a scangauge but you should be able to check if you can access the trans temp well before flushing.

Best way to get Amsoil is go to the website and sign-up for a 6 month preferred customer membership. This will allow you to get wholesale pricing on all of their products. There is a warehouse in Chicago and I was able to pick it up instead of have it shipped.

Actually opposite. Fluid entered the radiator at the top line. Fluid will exit the radiator from the bottom line.

Honestly, it did not make any difference as the overflow fluid during the fluid temp check was bright red, brand new, indicating that there was no old fluid left in the system.

Thanks for getting back here and for the correction! I was really hoping I had you wrong, and the system flows as I was guessing earlier. Now back to my Dr Frankenstein plans of how I will do the flush on the 4R....

Cheers!

Marde, Ziaman, or anyone else. If you can post a pic of the trans cooler and identify the hose to be used, that would be great. It certainly sounds a bit easier to access than going underneath. Thx!