So reading so many threads that have been posted on the issue surrounding 3rd Gen split core radiators and transmission cooling, I have become a bit curious. Seems the majority of the aftermarket installations seem to be the Tru-Cool or B&M. Some here have used the TRD transmission cooler which appears to be manufactured by Hayden. That cooler installation is designed around using the OEM radiator configuration as well as providing extra cooling.

One other issue that doesn't seem to be addressed in these threads is the fact that some of use are using electric fan cooling systems so the clutch fan is no longer installed. While this may or may not be germaine, it still is a concern. Most any external cooler would be in front of the radiator and while this may obstruct some flow through the radiator, you still have some pull-through cooling from the clutch fan. Many other manufacturers use an external transmission cooler attached directly in front of the radiator (Ford Ranger pickups and early Explorer, many Chrysler/Dodge model cars) with no additional cooling fans.

The question arises then is additional cooling using a seperate cooling fan necessary in all aplications? Some applications would be better suited to the seperate fan while others may not need it. So much seems to be based on application, location of operation (temperature of ambient air), towing, loading, 4x4 in desert locations, slow speeds vs highway speed and the list goes on.

For those who have done this modification to hopefully avoid the unintentional destruction of their automatic transmission, would the applicaiton of connnecting multiple smaller tube-in-fin coolers in series located in the frontal area near the base of the radiator vise a larger cooler with an electric fan placed be more cost effective? Is the addition of a seperate and thermally controlled fan an absolute?

One thing I did find out when I called several local toyota dealers here in the Northwest was that there appears to be relatively few 4runners of our vintage that have come into the dealers for service due to this issue of cross contamination of the transmission and radiator coolant. It may be selfish motivation for Toyota to not deem this a critical issue but many other manufacturers for many years have used the same technology for cooling the automatic transmissions. The response from the manufactuer is if you properly maintain your cooling system and automatic transmission at the prescribed intervals using the recommended OEM fluids, you should not have such a catastrophic failure (at least that is the theory).

So what are your feelings on this? I tend to want to bypass mine when I get everything sorted out, extra cooling should not be an issue. I definitely want to install two things in addition to the external cooling and that is a temerpature gauge to monitor transmission temps and a seperate external transmission fluid filter. As I experiment with the different coolers and configurations I'll post up results. In the mean time, feel free to chime in with your thoughts on this issue.

UPDATE
This is the preliminary install to try to figure out where they would be placed to maximize airflow to both the coolers and my radiator so I don't ahve to mount additional cooling fan



This is the completed install. I haven't hooked them up just yet but as soon as I get my gauge in and get it installed I will do a few tests before the connection of the new hoses to have a base line for the temperature.



UPDATE
I took MtGoat's recommendations on the building of the 'T' at my local Home Depot. I found the following parts:
3/8" Female pipe 'T'

Pipe bushing 3/8"MIP x 1/4"FIP This will be needed to extend the gauge kit adapter high enough above the 'T' so the temperature probe is not blocking the flow.

3/8" barb adapter


I also went to Auto Zone and bought the Sun Pro Style Line series triple gauge kit


I want to monitor both the inlet and outlet temperatures so I also purchased a single matching gauge kit.


This is what the 'T' looks like before and after assembly



More as it developes

Update: Installed replacement gauges and one to monitor coolant temp of the engine. https://www.yotatech.com/forums/f2/d...nstall-293175/

 

I installed the TruCool 4454 without an external fan, and will be getting a scanguage or something similar soon so I can check on my temperatures, but since my rig is only 4x2 and I don't tow very much, I think it will be more than adequate. I do live in Texas, and in the Summer it can get quite hot driving in city traffic, but I think mounting it just behind the grille should give it sufficient airflow to keep my ATF cooled. I believe that the majority of people here who have installed an aftermarket cooler have probably kept their stock fans.

 

Well, what is your application? I would only consider a fan on the tranny cooler necessary if you do a lot of mudding. Crawling must put a lot of load on the transmission but no air flow. Or maybe even if I pull a boat and sit at the loading ramp for a while. But when I haul it's usually at speed so I'm not going to worry about fan at all. If anything I'm just going to get a new radiator to replicate what was done by initial design!~

 

I'm concerned about strawberry milkshake as well and have read many of the threads here. I asked the Toyota dealer about this last time I was there and they said exactly what the OP did. "If you change your coolant and trans fluid regularly, with Toyota fluid we won;t have a problem". He went on to say that he has only seen one 4runner with this problem in 15 years. I didn't want to argue with him about it (already done enough of that for other reasons). Anyway, I certainly believe what I've read and seen hear. My personal solution is replacement of the stock radiator with a Koyo unit (A1998). I don't need the extra cooling and I'd like to keep the trans lines behind the radiator in the stock location. I expect to get another 100,000 from the Koyo then I'll replace it again.

 

The thing about dealership techs is that most aren't experts on Toyota Tacomas/4runners in particular so they don't know the little "quirks" of each model. They have to know a lot of general knowledge about the dozens and dozens of cars that Toyota has made over the years, but few have extensive knowledge on one particular model. Some do, but the majority don't. On the other hand, the experts here on YT know a great deal more about problems that are specifically related to Tacos and 4runners. I have learned loads over the years about my 3rd gen, but I wouldn't have a clue about most non-engine related problems on say a Supra or a Camry.

On the tranny cooler subject, I've always figured that it doesn't need a fan because the tranny isn't building up any heat if it isn't moving. If it is moving, then you've got the wind to cool. Feel free to jump in and correct me if I'm missing something, but it seems to make sense (at least to me).

 

I think the main reason guys install fans are for high-intensity, low-speed situations, like wheeling and towing on surface streets. For the average person using their 4Runner for a daily driver, I don't think a fan is necessary.

 

That makes sense, thanks.

 

This is my thought process too. Most of us are second, third or fourth owners of these vehicles. Who is to say a former well meaning owner did not flush the radiator and refill with the green coolant and tap water. It ran that way for a few years and the next owner had it serviced at a dealer and they flushed and refilled with red coolant and distilled. Damage was already done and the next guy gets the milkshake. I also worry that the cooler would not be as effective in the stop and go driving I do in the southeast. If I still own this vehicle in ten yrs. I will replace the radiator again to be on the safe side.

 

Is Prestone green antifreeze really so much worse than the Toyota red? And if so, why? Call me a heathen, but I don't think something is necessarily better just because it says Toyota on it.

 

I guess the main situation you are forgetting about is wheeling in lower gears up steep trails. That's where I've seen my highest ATF temps to date, and that was WITH a fan. I could probably go without a radiator fan too if I drove 50-60 miles per hour all the time.

 

Most of the Milkshake failures come after 100k where folks are 2nd or 3rd owners who might not be taking it to the dealer to fix. You can take this to any auto shop to fix or do it yourself like many of us do. I have no issues with just installing the new radiator and hooking it back up in line with my tranny cooler. If it goes again, that will be at about 320-340k miles.

 

Went to another yard today while I was out and about. Found several items related to the external transmission cooler mod, a.ka. "Strawberry Milkshake Mod". As I mentioned and have been posting questioins on a few threads and MT Goat has been giving some gr8 info on this topic, I am still looking for ways to cut the expense on the mod. So I asked a few of the Yard guys about what I was looking to do. The suggestion I go was to got with one of the external coolers out of the early Explorers (90-94). They have a very efficient and heavily built cooler. So I asked what if you ran two of these coolers in series? The response was they should do very well even without a fan, but in an offroading scenario, having a fan back up can't hurt, but consider that they will be in the front of the radiator near the bottom they still would get some cooling by the radiator fan just like they do in their native configuration in the Explorer. While the Explorer may not be the most highly thought of off road vehicle, it is an SUV. Something to consider.

So here are the coolers:


They are each 7.5 inches by 11 inches and .75" thick. These are not the typical fin & tube coolers but are specifically designed as transmission coolers so their makeup is more suited to cooling transmission fluid. The tubing is the OEM transmission tubing and will be utilized. Outlet of the first will feed into the inlet of the second.

Both units in their native installation are secured to the radiator frame and center post with 3 screws. The attachment on the center post is rubber grommet mounted. Preliminary measurements have indicated that they should fit when placed end to end as somewhat shown in the above photo as well as attaching at the lower radiator cross member while not hanging below the bumper frame which is right at the mounting location of the front skid plate.

Mounting here should give full air flow across/through the coolers as well as some protection from road debris. This is also the same area in the main radiator that the OEM transmission cooling coils reside. This area is still serviced by the radiator fan when operating so placement in this location should not affect nor reduce the normal cooling of the currently configured radiator.

The single speed electric fan is large enough to completely cover one of these coolers. Here is the fan:


This fan has full length mounting braces that are very heavy duty and would not normally bend in pretty most any application. This is the lowest profile fan I have found yet. It is only 2" thick from the outer motor housing to the fan blade inner edge when mounted against a radiator and still maintains approximatley a 1/4" clearance.


Now I know that Ford ATF doesn't work and play well with Toyota ATF so still need to figure out the best way to flush and clean the Ford coolers. I was going to use a solvent tank at the base but it's broken and they are awaiting a replacement and we all know how long it takes government to replace equipment ... So I am looking for other ways of doing this.

I want to try to configure the installation and maybe even mount the coolers to check all fitment and clearances. Ideally I want to add a temperature gauge to monitor the tranny temps. I may install this item along with one of those transmission spin-on filters. Seems most of these have the boss installed for attaching the temperature sensing lead. Any recommendations on the best set up? Brand names and where to obtain, mounting of the gauge etc. Let me know what has worked for your setup or what hasn't worked. Why reinvent the wheel! Thanks guys, looking forward to your responses

 

In my particular application, I mostly do on-road driving. The winter is the primary time I use my 4x4 with the exception of the monthly "maintenance" putting the transfer case in gear for about 10 miles or so. I do take it off road on occasion, but nothing like alot of the hard core guys (i.e. MtGoat).

Did a preliminary mounting of the two newly acquired Ford Explorer transmission coolers with ty-wraps to see where the best locations maybe. I will post up some pics later. Will have to fab up some brackets to mount these to optimize their location along with preserving as much traditional cooling for the radiator/AC. There would be so much more space there if that Condensor coil and plumbing wasn't there!

Still can not quite figure out the best temp gauge to use, where to mount it. Any recommendations on which one to use? Also, has anyone tried/using the external transmission filter, the type that uses a spin on filter?

 

Fitted up the first of the two coolers along with a couple of the mounting brackets, will post pics later today. Any suggestions on the gauges and filter?

 

Finally got to doing some of the preliminary fitment for the transmission coolers. To begin with, I needed to remove the grill guard, grill, horns and bumper.


Next up was preliminary hanging of the coolers to see which configuration would be the best as well as fitting them close to the radiator/condensor without interferring with any of the other components in the radiator area. I used black nylon ty-wraps.


This is still a bit sketchy but this will most likely be where the coolers will be located. I will require modifing several items including the cooler frames.



I have had to manufacturer brackets to hold the coolers at their ends and in the center. I utilized the center radiator support to mount a bracket inorder hold the cooler away from direct contact with the A/C condensor coils.




Still need to make the brackets for the left side cooler. The A/C freon piping is making it difficult to position the left side cooler so it will require moving the frames as well as manufacturing the bracket.

Here is the right side cooler temporarily installed:


As you can see I positioned the right side cooler low to minimize air flow blockage to the radiator. This should allow for enough air flow to the transmission coolers to provide for adequate cooling.

More as I continue

 

I had initially mounted my tranny cooler down low, and it didn't work very well as most of the airflow was blocked by the bumper. Since you have the second one though it probably won't be a problem.

 

Yeah that was my feeling on that as well. The bumper was a concern and if the A/C line from the left side of the condensor would have been in a different location it would have made the placement of the second cooler easier. I want to put a temperature gauge in before I put the system online so I have a base line to check temperatures against. Thanks

 

Updated info see first post

 

lurking along and stunned as usual by the thoroughness of the effort and details presented.

I'm a manny tranny guy but most of my 3rd gen buds and lady friends are Limited owners.

I sense severe overkill here for most folks' needs, but I can still appreciate the thought process involved. Once done I think we can point to this thread as the "Ultimate Auto Tranny Cooler set up for 3rd gen Runners".

For the average non off roader I would think a simple radiator replacement every 8-10 years or 100K miles or so is the cheapest, easiest and most effective solution.

But if I knew what I was talking about I sure would not lurk around here-you guys teach and explain- and it is most appreciated to view the logic at play.

 

I figured you were out there just looking over my shoulder! I wish I lived closer or vise versa as I noted you held a little get together concerning this very issue.

But you know me, try to use what is already out there. If I can minimize the actual outlay of cash for a project and can use someone else's technology (Ford, GM, Honda, Nissan) for less then half price of an aftermarket part, my labor is cheap!

I get alot of self satisfaction in the doing and accomplishing something I never tried before with my limited tools and access. Thanks for the comps Ron. I know what I do helps others along with the motivation to try something like this, but it is also gratifing to know that when you get told, thank you my friend