2008 SR5 V6 Transmission Spill and Fill Question

Hello. Long time reader - first time poster

I am somewhat new to doing my own transmission maintenance and have some questions about draining and replacing the ATF in my 2008 (gen 2) Tacoma. The trucks is a double cab v6 sr5 with 200K on the clock.

I looked around for the procedure for dropping the trans fluid and replacing it (just a spill in fill - not taking the pan off or anything like that) and found a procedure that basically stated to:

- drain the fluid at the pan drain and measure how much you get out
- replace the amount you took out and add a bit extra (like 1/2 a quart)
- start the truck and either monitor the atf temp with a scan tool, or jumper the odb2 (pins 4 & 13) to put it into the AT oil temp test mode (I opted for the later)
- once up to temperature, open the overflow tube plug and let the excess drain to a trickle, recap everything - and you're done.

So I did that, and got nothing out of the overflow. Okay - not what I expected, but my guess is that I was a bit low on fluid. So I added another quart and tried again. Same result. So I added another 1/2 quart. You guessed it - same result.

So I stopped at this point because this seems weird to me - but perhaps I am just being too cautious? So - my question - so long as I am following the procedure whereby I add some fluid (say 1/2 a quart), run the level procedure and open the overflow plug each and every time - I cannot overfill and damage the transmission, right?

(Some other things I investigated just to make sure I wasn't missing something... I did try opening the overflow tube with the truck off just to assure myself that the overflow tube was not plugged - it wasn't. The fluid that came out was much more red than the stuff I took out originally - so I am confident I am putting the new ATF in the transmission. I also check the level of my garage floor and the truck frame, not perfect but not far off either. Truck seemed to drive fine before going on my little ATF spill and fill adventure.)

 

If your getting it to temp (96-115F) with the engine running and opening the overflow you can't really overfill it.

 

Ok - that’s reassuring and kinda what I was thinking.

So my take away is that I should continue adding 1/2 a qt, re-run the procedure, repeat until I get fluid to come out of the overflow.

My other take away is that my truck must have been pretty low on fluid. I’m surprised it was driving and shifting as good as it was.

 

Also, do the procedure on leveled ground. Use an IR gun to help confirm the OBD procedure is working. I used to use just the IR gun; now have an UltraGauge. My IR gun reading is within 3 degrees of the UG.

 

There have been reports that some 2nd and 3rd gens were a quart or more low on fluid from the factory, I wouldn't expect it to have been much lower than that without exhibiting shifting concerns though.

I've never done a drain and fill on one but usually pan drop on one takes about 4-5 quarts to refill.

 

How much fluid drained out on your initial drain?

 

That’s an excellent question. I put a level mark on the container I used to drain it, then cleaned and refilled the same container up to the mark (plus a little extra) when I replaced the atf - so I never actually measured what came out. That being said, I’ll clean out the container tomorrow, fill it to the mark with water, and then measure the amount of water and report back.

 

At 200k miles I'd drop the pan, maybe your tube for the fluid level is plugged, seems strange not to get anything coming out after adding all that extra fluid. Dropping the pan and changing the AT filter would be my plan, especially w/ 200k miles w/ no prior transmission service. Here's my post on that (just did it last weekend,and have a lot of miles too 190k). You should get a bucket like mine that has qt. markings.
[URL="https://www.tacomaworld.com/threads...omatic-transmission.68462/page-72#post-304403

 

I did do a quick test to determine if the overflow tube was plugged - and it is not. Basically I shut the truck off, let it sit for a bit, and then opened the overflow - and got a good stream of fluid.

I have had some maintenance done in the past, but it is admittedly overdue. I figured I'd start with a spill and fill and see how it goes, and work up to dropping the pan. Worth noting that the trucks has spent most of its life in the northeast - so getting that pan off is likely going to be a very delicate operation.

 

So - I got a chance to measure the amount of fluid that came out originally - and it was just under 1.5 qts.

 

That is, like, NOTHING!

Doing a spill & fill should take almost a gallon (3-4 quarts) of fluid.

Are you sure that you are opening the transmission drain plug? IIRCC it is a 14mm. The level check is a 5mm allen.

 

Yeah, 1.5 qts. did strike me as not being very much.

Yes, I am sure I drained the trans using the 14mm transmission drain plug - and given the circumstance it’s a valid question to ask.

I won’t be able to get back to the truck for a few more days, but when I do get back to it I’m going keep filling and checking a 1/2 qt at a time and see how it goes - knowing I might very well have been (very) low on fluid.

 

So - finally got a chance to get back at it. Following the advice on this thread I was able to complete the fill and level procedure, and the truck drove quite well on the test drive. All told, I ended up putting about 4 quarts back into the system to get the level correct (1.5 quarts to replace what I initially removed, plus another 2.5 quarts).

So - what did I learn? I guess one take away was that my truck was pretty low on atf. My second take away - I did not realize my truck was low on atf because I did not bother to actually measure what I got out on the initial drain. Lesson learned.

I appreciate all the advice - thank you all

 

I exchange 12 qts via the transmission cooler lines to the radiator. I do 2 qts at a time. Pump out 2 qts, pump in 2 qts. Then I use an IR thermometer to make sure the pan is 90 to 110 degrees F and check the level running.

 

I did the same on my V6 but did a pan drop and new filter too as mine had never been done at 190k miles (just bought it). I used the gravity method (long funnel in engine bay running hose into AT fill hole) to fill and was super simple, took about 20 seconds to fill 2 qts this way w/ no drips and not getting under the truck I did drain out the lower AT cooler line, just so easy this way!

 

I pump out by starting the engine with AT cooler output line into a container. Takes a few seconds to pump out 2 qts. Then I pump 2 qts in using a cheap garden sprayer like https://www.walmart.com/ip/HomeGard...e-sprayer-for-Lawn-Home-and-Garden/2954123081 attached to the AT cooler return line. I also use the pump sprayer to top off. This is a fairly simple process.

 

The other day I happened to asked ChatGPT about "spill and fills" as I'm at 195k, thought this info might be pertinent to the discussion...

Since each drain and fill only replaces about 30-38% of the fluid in your 2008 Tacoma's automatic transmission, you’d need multiple cycles to replace nearly all of the old fluid. Here's how it works mathematically:

Each time you drain and fill, some old fluid remains, so the percentage of old fluid left follows an exponential decay pattern. Assuming you replace 35% of the total capacity (using an average of 4 quarts out of 11.5 quarts), here’s the approximate percentage of old fluid remaining after each cycle:

1. 1st drain & fill → 65% old, 35% new
2. 2nd drain & fill → 42% old, 58% new
3. 3rd drain & fill → 27% old, 73% new
4. 4th drain & fill → 17% old, 83% new
5. 5th drain & fill → 11% old, 89% new
6. 6th drain & fill → 7% old, 93% new

After about 4-5 drain and fills, more than 80% of the fluid will be new. By the 6th cycle, you're over 90% new fluid, which is effectively "all new" for practical purposes.

If you want to speed up the process, you could do a full flush using the cooler line method, but multiple drain-and-fills are a safer method to avoid shock to the transmission. Let me know if you need more details!

 

Nice info for sure, thanks for posting this. I did the full pan drop, new WIX filter, & Maxlife ATF flush (11.5 qts out, 12 qts in and drained the 1/2qt extra at proper ATF temp). Hopefully no shock to the AT, has 190k miles w/ no prior service. I will say it's shifting w/ solid shifts, and seems to be an overall improvement thus far, hopefully there will be no adverse effects. The Tacoma is in immaculate condition, the Carfax was one of the best I've ever seen, dealer service every 5k miles w/ every req'd service done throughout it's prior 10 year life. I've read pros & cons regarding doing a full flush, if the Tacoma had evidence of being driven hard and if the ATF had a burnt smell I'd be more concerned. The ATF I drained other than being dark brown seemed to be in good condition, and not a lot of sludge on the pan magnets, so hopefully all will be well for another 190k!