Finally got around to flushing my trans with Amsoil synthetic

[akauth]

I'm just finishing up my 30,000 mile service tasks (have been doing them little by little over the past 4,000 miles). Changing the thermostat and coolant today for the radiator.

You know, I've run synthetic in a trans for years, but I really am surprised that putting synthetic (well, specifically Amsoil ATF, but that shouldn't really matter) does significantly smooth out the Tundra trans.

I'm not sure if the OEM ATF is just thinner (like 5w20), or if the viscocity range of the AMSOIL is so much better (certainly from wear and stability perspectives it is superior to any regular fluid, Toyota or not) but when I flushed my trans with 16 quarts of Amsoil - actually, it might be a little more or less, I started with 5 gallons of ATF and it looks like I have about a gallons left, I had a definite improvement.

But there is noticable lack of vibration on the floor. I didn't notice it until it went away. Kind of like hearing a light buzzing sound and then suddenly realizing when it's dead quiet again.

But I do notice that when "pushing" the vehicle ahead by putting the pedal down quickly (like a fast lane change), that it moves ahead more smoothly even when it has to down shift.

Now granted, the trans is very smooth. But I definitely notice that there is less vibration (that I didn't even realize was there) and the shifts are cleaner.

I don't know if my gas mileage increased, it usually does, I haven't taken a trip yet to be sure.

I happened to grab the return coolant line and I'm also pretty amazed at how cool that fluid is heading back to the trans. If you've got a cooler and are using regular fluid, that's going to go a long way toward keeping that fluid in great shape. That return line fluid is definitely not even getting hot enough to burn you good if you spilled it on you. It's amazingly cool.

Toyota did a GREAT job on that. Mine is a 2000 so I got the cooler standard.

Anyway, fyi. I give a big thumbs up to synthetic performance in the v-8 trans. It shouldn't really be noticable as it is just ATF, but it is. Even if it didn't increase the engine life. I'd recommend a move to synthetic because there is even less vibration then there is now (which isn't even noticable until it stops, then you know it was there).

Personally, I use Amsoil (mostly everywhere on my vehicle), but I image Mobil1 or Redline would be fine too. Redline might even be better.

alan

[nj1266]

How did you flush your OEM tranny fluid and fill the synthetic? Could you give us a step by step description?

[Stooge]

Search the site - lots on exacly what to do. The lower hose to the air-to-oil transmisstion cooler in front of radiator is the pressure line. Disconnect it, insert a 1 foot section of 3/8" copper tube and bend it down in front of the radiator under the bumper. Put that end in a gallon jug marked at about 1/2 (two quarts). Start the engine, fill jug to line, stop engine. Dump jug, add two quarts SLOWLY down the dipstip for tranny. Repeat until 12 to 15 quarts are changed through. Reconnect everything. Check the fluid level and leaks. Your done. Next day, check fluid level again. So easy you should do it every year!!!

[akauth]

Originally posted by Stooge
Search the site - lots on exacly what to do. The lower hose to the air-to-oil transmisstion cooler in front of radiator is the pressure line. Disconnect it, insert a 1 foot section of 3/8" copper tube and bend it down in front of the radiator under the bumper. Put that end in a gallon jug marked at about 1/2 (two quarts). Start the engine, fill jug to line, stop engine. Dump jug, add two quarts SLOWLY down the dipstip for tranny. Repeat until 12 to 15 quarts are changed through. Reconnect everything. Check the fluid level and leaks. Your done. Next day, check fluid level again. So easy you should do it every year!!!

Actually, there is an easier way. Use the UPPER fitting on the Aux cooler instead of the LOWER fitting. Someone mentioned it on here and they are right. It's easier. This is what I did:

Before you even start stop by an auto parts place and get a 3 foot section of 3/8 inch rubber transmission line. Also, pick up the transmission crush washer from the dealer. (I keep a couple of all the various Tundra fluid/oil washers in my tool box so I don't have to run to the dealer to do a fluid change. )

I park on a slight hill so the front is a couple feet higher than the rear (oil drains downhill with some force). Putting the front wheels on ramps would do the same thing.

Park the vehicle for a couple minutes to let all the fluid drain into the pan and then check the transmission dipstick to see what the fluid level is.

Important:

You want this to be the level when you are done flushing. Actually, you want it to be just a little less so you can add some later to top it off after you've checked the fluid level while "hot". Be conservative, don't overfill.

Drain the ATF in the transmission pan by pulling the drain flug (think it's 14 mm). WHILE the plug is still out, pour a clean, full quart of ATF into a funnel inserted into the dipstick tube to flush out any dirty fluid left on the bottom of the pan. (I do this on all oil changes - diff, trans, engine, transfer).

After all the fluid finishes draining, put the plug back in (with the new crush washer) and tighten it to 15 foot-pounds. Fill the pan with 4 quarts of fresh fluid ( I suggest synthetic) using the funnel in the dip stick tube.

Go to the front of the vehicle and throw an old t-shirt under the fittings going into transmission cooler in front of the radiator (to catch any drips when you disconnect the UPPER line). Not much fluid will drip, but this will catch anything that falls.

Disconnect the UPPER fitting on the transmission cooler. This is the return line back to the transmission. Feed one end of the 3 foot section of 3/8ths inch transmission line through the hole in the middle of the bumper (behind the license plate) and connect one end to the UPPER fitting on the tran cooler. You won't need any clamps, it will fit tightly enough. Just squeeze it on and this will divert the transmission fluid into a drain bucket rather than back to the transmission.

If you want you can leave the temporary drain line above the bumper rather than through it, but I keep my truck clean and I didn't want any ATF drips on the clean paint when I pulled the line off. I guess you could run it under the bumper too. But through it worked best for me.

Put the other end of the temporary drain line into a bucket that has graduated marking on it so you can tell how much fluid is in the container in 1 quart increments. I used two 2 1/2 gallon containers and built a dipstick so I could tell how many quarts of fluid were in the bucket as I couldn't see from outside the container how much fluid was in it. I had to tell from inside (and at night). A dipstick worked fine.

Once you've got one end of the temporary drain line connected to outlet (the UPPER fitting) of the transmission cooler and the other end into a container(s) that will hold 4 gallons total of ATF you're ready to go. If you connect to the outlet, you'll have the advantage of flushing fluid through the cooler also. Plus, it's easier to use rubber hose.

NOTE: If you don't have the aux transmission cooler, then connect this drain line to the OUTLET on the transmission cooler that is in the radiator rather than the OUTLET on the auxilary cooler. You can still use the same 3/8 inch rubber trans line either way.

Start the vehicle and let your drain bucket fill with 2 quarts of fluid. This will only take about 20 to seconds or so. Maybe even less. But I suggest that you turn the vehicle on, then turn it off 3 seconds later the first time just to make sure that everything is draining as you expect and that you're not making a royal mess.

Once you have two quarts of fluid in the drain container. Stop the engine and put the same amount of ATF into the dipstick tube.

Run the engine again and drain another two quarts. Stop the engine. Fill the trans with another two quarts. Repeat until you fill the container, then swap for another container (if you need to).

Keep doing this until you see clean fluid come out which will take about 11 quarts. Personally, I flushed close to 16 quarts through. I had 5 gallons of synthetic ATF when I started and had about a gallon left when I was done.

Check the fluid level before you pull the drain line off (so it's the same level as when you started or a little less). This is the STOPPED level of fluid that was in the pan with the vehicle oriented on whatever level or unlevel ground you have chosen to drain the vehicle on. So give the fluid time to drain down - couple of minutes will drain a vast majority of the fluid.

If it's not too high, pull the drain line off and reconnect the original transmission line back to the upper fitting on the aux transmission cooler. (Or the transmission cooler in the radiator if you don't have an aux cooler.) It's best to leave it a little low when you pull the drain line as more fluid will drain down the longer you wait (but not much more).

Drive the vehicle for 20 minutes and check the fluid when it's warm. I'd still leave it just a touch low. Just above the low mark. Then top off the last little bit if needed after you've driven it for a couple days.

Don't overfill. If you do, drain the extra fluid off before you run the transmission much.

That's all there is to it. I prefer to drain the ATF directly into the containers that I'm going to take to the recycling center. I use two 2 1/.2 gallon containers myself to catch the fluid and just swap the drain hose from one container to the other as I go along. Too, I was doing it in the dark with the help of a flashlight.

Clean the 3 foot drain hose and put it in a plastic bag and you can use it again later.


Alan

[v8Toilet]

I just totally exchanged my transmission fluid with 16 quarts of Mobil 1 synthetic automatic transmission fluid at 39,466 miles and did it myself. I'm always very skeptical about the claims people make about automotive products (have seen so much crap and scams) and I try to use as many facts as I can when I make a claim.

My transmission has always shifted a little firmly especially the 1-2 shift. It has never been harsh like some people have claimed. It also seemed to be getting a little harsher with age but I can’t say for sure. I can't back this up with any factual data but after switching over to synthetic fluid I can say that the transmission does shift more smoothly.

Here is what I noticed most. When I first drive it in the morning the transmission shifts quicker than it used to or it shifts more like it did with the regular fluid when it was warm. There isn’t much difference between hot and warm anymore. I have put over 100 miles on it now and I have tried but I can't get the transmission to bump into gear like it did before. The transmission hasn't done it once. It seems to work more smoothly now.

I think the transmission shifts quicker when it is cold because the synthetic fluid flows better in low temperatures. I hope that the transmission shifts are less firm when warm because the better flow characteristics of the synthetic fluid make it easier for the transmission to control line pressure. I don't want a clutch pack to be slipping more than normal as they engage because the fluid is slicker.

When I felt the fluid between my fingers it did feel very slick.

[akauth]

Originally posted by v8Toilet
I just totally exchanged my transmission fluid with 16 quarts of Mobil 1 synthetic automatic transmission fluid at 39,466 miles and did it myself. I'm always very skeptical about the claims people make about automotive products (have seen so much crap and scams) and I try to use as many facts as I can when I make a claim.

My transmission has always shifted a little firmly especially the 1-2 shift. It has never been harsh like some people have claimed. It also seemed to be getting a little harsher with age but I can’t say for sure. I can't back this up with any factual data but after switching over to synthetic fluid I can say that the transmission does shift more smoothly.

Here is what I noticed most. When I first drive it in the morning the transmission shifts quicker than it used to or it shifts more like it did with the regular fluid when it was warm. There isn’t much difference between hot and warm anymore. I have put over 100 miles on it now and I have tried but I can't get the transmission to bump into gear like it did before. The transmission hasn't done it once. It seems to work more smoothly now.

I think the transmission shifts quicker when it is cold because the synthetic fluid flows better in low temperatures. I hope that the transmission shifts are less firm when warm because the better flow characteristics of the synthetic fluid make it easier for the transmission to control line pressure. I don't want a clutch pack to be slipping more than normal as they engage because the fluid is slicker.

When I felt the fluid between my fingers it did feel very slick.

The cold flow will make somewhat of a difference, but what will make a much bigger difference is that when it's warm (actually hot) the fluid will thin less than regular fluid. So less downshifting is needed (it's more efficient).

[v8Toilet]

I must say though that I have been changing my own transmission fluid for years and this is the first time I used synthetic. When I would change the fluid in my other cars I would notice a slight difference too with the regular stuff so I can’t attribute all of the differences to the synthetic.

[akauth]

Originally posted by v8Toilet
I must say though that I have been changing my own transmission fluid for years and this is the first time I used synthetic. When I would change the fluid in my other cars I would notice a slight difference too with the regular stuff so I can’t attribute all of the differences to the synthetic.

That's definitely true. If you do a change, usually you'll have an improvement for a period of time. The difference it that it won't fade when using synthetic like it does for regular ATF.

However, downshifts should be a lot less due to the viscosity improvement.


Alan

[cappi]

I'm sure Alan's procedure will work also but I just followed the directions in the "Garage" for an entire change. I used Mobil1. The directions in the Garage worked perfect... and very easy too. Actually, was easier(although longer) to change the ATF than to change differentials and transfer cases.

[Trouthead]

Now if you put in a magnifine filter in the feed line to the trany cooler you will be complete. The Tundra trany has no filter internally, only a screen. the magnifine filter is a 5 minute job and the filter cost 20 bucks. Cheap insurance. I put on ein a couple of weeks ago, just a little bit more piece of mind. I had a friend who change fluids in his caddy trany at 60,000 miles. Used conventional, and the trany blew at 110,000. Cost was about $3000. A filter and synthetic is real ceap insurance.

[akauth]

Originally posted by cappi
I'm sure Alan's procedure will work also but I just followed the directions in the "Garage" for an entire change. I used Mobil1. The directions in the Garage worked perfect... and very easy too. Actually, was easier(although longer) to change the ATF than to change differentials and transfer cases.

That advantage that I found for the using the top line as someone else suggested on here first is that it's a lot easier to connect a piece of trans line to it and drain the fluid to whereever you wanted. There is also the advantage of flushing the cooler, which you can't do otherwise. But that's a pretty minor advantage. Too, if you DON'T have a cooler standard, you can just plug the drain line into the outlet of the cooler built into the radiator instead and put the other end in your container.

Kind of six of one, half dozen of another, but I think it's much more convenient to use the upper fitting as you'll only need an extra length of trans line to drain it while not making any mess.

Alan

[akauth]

Originally posted by Trouthead
Now if you put in a magnifine filter in the feed line to the trany cooler you will be complete. The Tundra trany has no filter internally, only a screen. the magnifine filter is a 5 minute job and the filter cost 20 bucks. Cheap insurance. I put on ein a couple of weeks ago, just a little bit more piece of mind. I had a friend who change fluids in his caddy trany at 60,000 miles. Used conventional, and the trany blew at 110,000. Cost was about $3000. A filter and synthetic is real ceap insurance.

I agree. Unfortunately it doesn't guarantee that the trans will last 200,000 miles with good maintenance, but it makes it MUCH more likely.

Alan

[Henk]

I changed mine at 30K to Amsoil. I think what akauth said earlier is true about thinning less and being more efficient. I immediately noticed the cruise control "downshift" problem almost disappeared. A pleasant surprise.

[Trouthead]

Alan,
You are right there are no guarantees of 200,000 miles. I'll never keep anything that long but I think sythetic and a filter will just about guarantee 150,000. but that is good enough for me.

[akauth]

Originally posted by Trouthead
Alan,
You are right there are no guarantees of 200,000 miles. I'll never keep anything that long but I think sythetic and a filter will just about guarantee 150,000. but that is good enough for me.

I totally agree with you there. Anything to avoid chunking out the $2500 it costs to repair an auto trans is a great idea in my book! That's the reason that I run synthetic also.


Alan