Transmission cooler questions

Did the install his morning. I was way overthinking things. I picked up some aluminum bar stock and M6 nuts bolts and washers at ACE yesterday and just winged it. Relocated the horn and pretty much followed what everyone else did. Test drive around the block and no leaks. Worst part of the whole job was wrestling with the skid plates, but they always give me fits. Was going to do a real road test but we’re about monsooned on.

 

I’m going to start the process of swapping the ATF. It’s been like 40 years since I’ve had to do differential equations but if doing this right, assuming here is no breakdown in the combination of old and new ATF (read didn’t drain and fill and then go drive the balls off the truck) the biggest improvement in ATF quality when replacing 1/3 of the ATF at a time would be seen in the 2nd and 3rd iterations. After the 5th iteration I’ll have less than 1% of the old ATF remaining and beyond that it’s probably not worth the effort.

 

Never want to mix brands.....if you switch, complete flush is needed.
Which is simple to do while installing a cooler......just have put in at same rate u take out....so it dont run dry.....

(304) BEST Method Transmission flush '95-'04 Toyota Tacoma √ Fix it Angel - YouTube


Thats problem with buying a used truck.....no telling what was used....

 

What’s wrong with mixing brands? Assuming they conform to T-IV.

 

Once upon a time I did a standard drain and fill, filling with Mobil 1 full synthetic ATF and I had no consequences. That was years ago. I don’t see the issue if it’s a compatible formula or exceeds the requirements.

 

It's not going to hurt anything. Most automotive fluids these days are compatible with each other as long as they're the same type. If they weren't imagine all the non-mechanically inclined people in the world that would cause so much damage.

It's like mixing gasoline brands, they all use different types of additives, so best to stick with one brand often if possible, but nothing bad will happen. Possible that there could be an incompatiblilty but chances are very rare if at all.

I started off by doing drain & fill on my truck also, never worried about it, never had an issue.

 

Yes I would never mix the old toyota oem with new maxlife synthetic atf....
Too me that would be like mixing toyota brake fluid with prestone max synthetic..
dont do it.....
I put in a moderate amount of time and money flushing mine....
Think I used 4 and half gallons....and mine is the smaller size....like 9 quarts......counting TC......

Torque convertor is tough to flush.....and its most likely first thing to go out if neglected.....Mine, the small one, start at $400 and go for rebuilt/new aftermarket ones...

 

We all talk about flushing out the old & dirty transmission fluid from our 20+ year old Gen 1’s, but we don’t talk about the need to replace the 20+ year old rubber lines. I read where the deterioration of the rubber transmission lines is the number one cause of contamination of the “new” fluid. Has anyone else read or heard this? We replace our upper & lower rad hoses, when should we replace the transmission lines? Thx!

 

If you are worried about it or suspect a reason to might as well. There's only the 2 going into the radiator and they're not very long as they are connected to hardlines attached to the trans. IIRC they don't have molded bends so no need to buy OEM, so it'll be cheap. Just make sure you buy trans cooler hose & not fuel/heater(coolant)/vacuum hose.

When I installed my trans cooler I replaced one of the hoses completely cause it needed to be longer (but that was 2010). The one coming from the trans to the radiator is still stock on mine. I checked it maybe a year or 2 ago, wasn't rock hard yet. Thanks for the reminder, I should probably check them the next time I have the skid plate off. I just had it off 2 days ago too.

 

Crazy.....some are still using the factory hoses on steering and tranny....

Makes no sense....if you lose tranny hose, you destroy the trans in couple minutes if you dont catch it right away...
As far as steering, your ruining your rack with dirty old fluid with rotting hose bits mixed in.....
And in the flex brake lines.....if one breaks, you lose whole brakes....

In regular industry recommendation is every 5 years.....especially those that could cause harm or loss of life....

 

Thanks! Sounds like I’m buying and replacing some trans cooler lines. Not to mention the steering rack too! I was just focused on the trans I didn’t give the steering rack a second thought!

 

You can buy gates hose by the foot anywhere for the tranny....

The power steering hoses set me back almost $300....took a week to order them..
Steer one has 3 mounts securing its route...the ones you need rubber arms to get to...... PIA that was....

Just kills me when someone goes and buys one of these thats had no love for 20 yrs...and they say its a money pit.....

Premium lines you've got to be careful when buying used,.... some privilege people buy these, camrys, lexus, ect,.....and then run the wheels off doing the least amount to get by.....
I've seen a number of camry's with engines shot at 200K because of the owner liked skipping oil changes....VVT's dont like that....

 

Well sheeeiit, I replaced my rubber cooler lines when I did my remote cooler and filter install. So they’re only about 4-5 years old. Ancillary win.

 

3/8” ID, correct? (trans lines) Thx!

 

I actually directly asked this question 4 months ago (should I switch to synthetic atf?) The collective response was the opposite of what you're suggesting now. I went ahead and did a drain and fill with MaxLife ATF (essentially mixing 21 year old ATF with new ATF) and have not experienced any negative effects. My next drain and fill will be 2 weeks from now (once summer obligations subside).

 

When I swapped the return line, I pulled the stock and just let it drain. 1.5 quarts of fluid. Replaced with MaxLife ATF as well. Worried? Nope.

 

I've got two videos on this subject matter so I figured I'd share them.

https://www.youtube.com/embed/2nVbwe2t2T8

https://www.youtube.com/embed/34wnfq85_qk

 

What I tried to show in post 22 was the results in terms of % of old ATF left in the transmission when repeatedly draining two quarts and adding two quarts. I based it on a total capacity of 6 quarts but the A340 hold a little over 7. The results are still basically the same, after you’ve swapped the 3 gallons 2 quarts at a time there’s around 1% of the old ATF left in the transmission.

So this weekend I’ll take my 3 gallons of MaxLife, drain 2 quarts, add 2 quarts, drive around to get the truck up to normal operating temperature to make sure the new stuff is mixed with the old and then repeat until I’ve swapped all 3 gallons, 2 quarts at a time. I’ll keep the ATF I drain each time in separate containers so we can see the results. If I’m right it should be hard to tell the difference between what I add vs what I drain by the time I’m done.

 

Thats the beauty of that little pump....every 6mo I can draw 2 qts out...and then 2 right back in...
Best $17 I ever spent....and have used it for bunch other things..

7 qts seems a little low...I have the a43d trans and mine is closer to 9qt....
spec's say my little 2rz engine oil is 5.8qts......thats wrong.....its actually 4.5qt w/filter...and pretty sure after couple dozen times....

 

I think you're missing the point of a drain and fill vs removing the return line. If your goal is to replace all the fluid in one day, then you want to follow the remove the return line process (see Timmy's videos above). Drain and fills should be done over the course of a few hundred miles or so, changing incrementally (as your maths suggest), should give the gunk in the transmission time to filter out, vs "shocking" the system and replacing all at once.