I'm at 145,000 miles on my 08 SR5 and have not had the transmission fluid changed or flushed. It is still the original fluid. I did this because someone told me that I did not have to change the AT fluid on these as it is good for the lifetime of the vehicle. In the past 2 months, I've noticed that when the transmission gear shifts between 1,200-1,400RPM, there is a vibration or shaking that occurs until I let off the gas. This does not happen if I accelerate quickly. It only happens when being really smooth on the gas or accelerating really slowly. This weekend, I went underneath the truck to apply some fluid film and noticed some oil around the transmission pan. I could not see it leaking anywhere so I don't know if it was ATF fluid or oil from something else.
I'm not sure what I should do at this point. I typically stay away from the dealership as I try and do most of the repairs myself that I'm able to, but to drain and change the AT fluid looks like a real pain if one does not have a lift. I typically bring my vehicle to a place that specializes in Toyotas for things that I can't do myself. Does this sound like an issue with the transmission cropping up? If so, what do you guys recommend I do? Should I bring it to a dealership, the Toyota specialist or try and do this myself?

Fluid exchange (Not a flush with a machine)

Get all that old crap out.

I have personally used both of these and am a definitely amateur DIY mechanic who has never owned an auto until my Toyotas.

Pick your transmission!

A750F 5 speed

https://www.youtube.com/watch?v=gx5dU3UVcRs

4 speed with dipstick (This is actually so much easier as you can refill via the tube)

https://www.youtube.com/watch?v=RumPXivBlk8

The first thing I would do is just check the level of ATF. If low, add some and see what happens. In some cases, it is a bad idea to replace the ATF if the vehicle is high mileage and it has never been changed. I think that 145,000 miles is not all that bad on a T4R but I must say that a trans fluid change doesn't often fix an issue. (IMHO). If you do change it, just drain and fill using OEM ATF - do not flush. It's actually pretty easiy to do yourself. If you want to exchange more of the fluid, run it for a while and do the drain & fill again.

Search “rumble strip issue.” I’m not that familiar b/c I haven’t had the problem but that’s what I thought of when I read your symptoms.

Also, you can do the fluid exchange. There are some great write ups. The only real pain is checking the level on the sealed models.

Very interesting, Bluesky. I was unaware that this torque converter lock-up chatter was a Toyota thing. It is fairly common on Honda Accords and I see it on my '04. It's generally described as a shudder as the torque converter locks and unlocks under very light load. When you accelerate, the torque converter does not lock so it does not occur. This is in fact a problem that changing the ATF does correct in my Honda - I drain and refill every 30,000 miles and it fixes it. There is an ATF additive product that claims to fix it if it's fluid related but I have never used it.....the video on their site is interesting.
Instant Shudder Fixx - Lubegard

I too had torque converter shudder/chatter. I suggest saving existing fluid that comes out in a clean plastic bottle. A way to check fluid level is to open the special tranny plug at the exact fluid temperature for just this specific purpose. No fluid will come out if tranny too cold or low level. Then add a small amount new fluid in the other fill plug and repeat running engine till tranny fluid at correct temperature. Then open special plug till fluid comes out and stops draining out at correct temperature and fill level.
So you wind up overfilling a little so you can see it drain out the special plug.
It is a weird process. Best to have an experieced Toyota mechanic do it while you watch for for your first time. The color of fluid drained out will give clues if you need more fluid replacement.

I’m with SurferUK, get that old crap out. Car manufacturers are irresponsible by peddling this lifetime fluid bullshit. They are not interested in your car lasting, they want you to buy a new one with low advertised maintenance cost. Sure, it will get you past the warranty but after that you are on your own. It’s an easy job, just a bit time consuming is all. And use the Toyota WS fluid.

The safe wisdom is to not SHOCK the tranny by a complete fluid change.
See how dark the existing fluid actually is by extracting a couple of ounces with a plastic syringe thru the FILL plug, I would save in a clear plastic bottle(like 16 oz water bottle).
The recommended procedure is a drain and refill. This only swaps out some of the total fluid. Then drive 4runner and see effect. If you think more new fluid is required. Just repeat the above process. If the color does not improve to a slightly brighter red, you may have sediment gunk in the bottom of pan.
Discuss with your trusted independent Toyota mechanic to find out if removing the pan & cleaning is a smart move or not.
If the fluid is beige in color you are seeing ground up torque converter lock up clutch friction lining from the shudder/chatter.
My 2 cents.

Thanks everyone for the responses. I think I'm going to attempt the drain and fill myself rather than bring it somewhere. I'm really curious to see what the color of the fluid is. Will post more as I get into the job.

When you decide to start on the drain/fill, make sure you can loosen the fill bolt first, then do the drain plug. It needs a 24 mm socket and bolt is located on passenger side of tranny. You'll also note theres two plugs at bottom of tranny pan. One is the drain plug and the other plug is for the overflow tube ( it'll let any extra fluid out to give you the correct oil level after oil is correct temp ). Unless you are much larger than me ( 180 lbs @ 5' -9" ) you can do this without jacking up you vehicle. To fill tranny after draining you'll need to get a hand pump that fits into a regular 1 qt bottle to tranfer the oil ( pump readily available from hardware/auto parts store ). Much less swearing with this method.

Thanks 4R005. Should I also drop the pan and clean it out or just do the fluid change? The pan has never been dropped so this would be first time doing this. Also, which method did you use (or recommend) to check the temperature? The OBD jumper method or using an infra-red laser thermometer?

I would recommend against dropping the pan unless you need to (seems like you don't need to).

Here's the DIY I used: ATF Exchange (using the cooling line)

Had the same symptoms as you around the same mileage (160k). Following the DIY fixed things.

For those claiming a full fluid exchange will "SHOCK" the tranny that is 100% false, the horror stories are from using a machine to FLUSH the fluid out under pressure & almost always on different makes or older designed GM transmissions or trans in bad condition to begin with.

For these Aisin made trannys in 4th gen 4runners they actually recommend a FULL fluid replacement at 100k miles (60k if towing or abuse) in the owners manual. A drain & fill only replaces about 2.5-3qts which is not even 25% of the total fluid... a D&F is better than nothing but a full exchange using the trans pump 2 qts at a time then refilling with a raised funnel & line into the fill hole on the trans is the fastest & easiest way to do it, can also use the cooler lines or a hand pump but takes longer, use gravity & a funnel held up or hung by the hood, I had a helper hold the funnel above the passenger fender while I added teh fluid. Pump out 2 qts with the trans pump (start & run engine briefly) then shut off engine & refill what came out.... after about 6 cycles of that 100% new fluid will be in there and it will not SHOCK a healthy trans regardless of miles.

As for fluid, there are many modern ATF's that are rated for WS use and will work perfectly fine if not better than WS... most use valvoline maxlife with excellent results, a few even reported it fixed their shudder issues. Old fluid looses anti shudder & other additives so replacing with new is the best way, drain & fill only gets 25% out each time then drains some of the new fluid every time after that. Do it all if you can, its no harder than a drain & fill. I used maxlife on my 08 V6 sport over 5 years ago, improved the shifting and is doing great with zero problems... maxlife is full synthetic too where WS is not, so handles heat & stress better. Also no need to drop the pan, these trannys use a metal screen filter & almost never need replaced or cleaned.

Lots of tutorials on here or vids on youtube of how to do it, tacomas of this era have the same trans so info on them applies to the 4runner too. Good luck whatever you do... its a good idea to download the Toyota service manual too, tells how to check the trans temp with the factory gauges & not guess with a hand held thermostat.