Auto Tran Faliure due to Radiator Fail?

Dang. I just read up on 3rd Gen 95+ 4Runners having the same problem. I found this thread most revealing: http://www.yotatech.com/f2/any-body-ever-crack-opened-up-oem-rad-if-not-here-we-go-194976/ And this one too: I saw where one 4Runner owner installed an external trans cooler with a cold weather bypass. I suppose that would work for our trucks too.

 

OP here with a quick update.... I'm out about 2500 miles from the transmission rebuild and still going strong. Only issue thus far, and I'm not certain it is related to the transmission job, is two occasions when the truck would not crank. Not sure if neutral/park safety switch was the issue or not. It eventually turned over with no problem.

Cheers!

 

I have been reading about this on other forums. It becomes somewhat common with patterns on certain vehicles and brands.

FWIW, this is the dreaded Strawberry Milkshake if you search the internet.

Even though my truck has around 25k miles, I'm pretty certain I'll go 100% external cooler and use the existing trans cooler for a power steering cooler.

PK

 

have an 08 4sp auto,is way to tell which model or is problem on both?

 

Without the radiator cooler, the trans will shift poorly till it warms up. It brings the trans up to operating temp faster.
It will probably be fine in the summer, in Florida. Don't go north

 

This kind of stuff happens. I don't believe there have been enough cases on the Tacomas to support everyone worrying right now. Keep an eye on the overflow when you check your oil and and open the radiator cap when the engine is cold from time to time. If you spot something that looks delicious but smells funky, then take action. With the volume of these trucks being sold, there will be some mechanical issues(doesn't make it ok). I have seen 1 GX470 that was starting to swap coolant with transmission fluid, and not one since. It was caught in time and the appropriate fluids were flushed.

 

Wondering this as well i have the 4cyl 4 speed auto, This issue isolated to the 5speed auto ONLY?

 

This makes me challenge the standard practice of routing transmission fluid through the engine radiator at all. An automatic transmission generates its own heat. With B&M's or Hayden's LPD(low pressure drop) transmission coolers available today, or Tru-Cools thermal bypass, I am thinking real hard on bypassing the radiator alltogether and using a larger transmission cooler than would be typically called for.

 

is the problem with towing setups.possibly pushing under sized rads,as you alluded to,i can remember when a 3 core rad was quite common,the external cooler is still a good bet,i have a standard 4spd auto/4cyl no tow pkg,although i would like to add a tow setup for occasional use with a small utility trailer.

 

canucktacoma, As far as the contamination goes, the problem is cheaply made radiators that develop a leak inside. The 3 core radiator you mentioned was probably a brass and copper radiator, not the aluminum and plastic of today. The transmission coolers today are made better than the radiators.

An auxillary transmission cooler would be recommended for your purpose. Whether you choose to use a small cooler and the radiator together in series or go with a dedicated larger dedicated cooler is your decision.

 

wolftree,,any better after markt rads or just keep replacing/modify oem models.

 

canuck, I am not finding any what I would call quality after market radiators for 2nd generation Tacomas. There seem to be some available for 1st generation.

 

Does anyone know what size line / hose Toyota uses for their transmission to cooler / radiator lines? I want to start assemblying the parts to install a cooler and remote filter and do away with the radfiator connection alltogether.

 

The hoses are 10mm but 3/8" works fine.

I have already mounted the remote filter and have been running it for a while.

My truck has the oem aux cooler / towing package. With the scangage it is still common to see temps of 165 or more.

I bought a new cooler that will eliminate the radiator fluid to fluid heat exchanger.

One thing about all the comments regarding the tranny fluid running too cold, it is not that big of a deal. If you start your truck and warm it up for 60 seconds, then drive, the tranny fluids are still only around 80 with outside temps of 70. The temps typically will only come up in applications slipping the converter.

My oem trans cooler will become a power steering cooler, which I may remote filter in stead of the current Magnafine filter.

I got the largest cooler for the trans that will fit realatively easy, a TRU-Cool (Dana or Long manufactured) M7B, which is 11"x8"x1.5".

As I posted before, I got rid of the Toyota WS fluid also and went with Mobil 1 atf.

PK

 

Please write up your mods so that others can learn from them. It sounds like you have a nice plan!

 

PMK, Thank you

 

Bundling some info previously posted.

http://www.tacomaworld.com/forum/te...te-automatic-transmission-filter-install.html

PK

 

PMK, I have been looking at several of the cooler manufacturers. All seem to be similar, so I am trying to narrow them down on the type of connections / fittings.

For others interested in adding a remote filter, look at Perma-Cool for their filter mounts. They offer several styles, size fittings and left, right, up ports to ease your installation on different vehicles.

 

If installing the external trans cooler, doesn't it defeat the purpose to still use the radiator cooler?

I live in MA and have concerns about cold weather..any thoughts?

 

Chuck,

I do not mean to intentionally revive an old thread, but I thought you may be interested to learn my 2006 Prerunner has experienced the exact same issues as yours. I have actually had the clunk 4/5 shift and speed bumps/rumble strips transmission issue since the truck was practically new. I also experience occasional hard shifts, like the a truck has had a shift kit installed. My transmission has been replaced three times by Toyota, but the issue always returns after a time. My Taco is now long out of warranty. The last episode of tranny issues happened in November with 141,000 miles on the clock. The truck was still drivable, so I decided to just live with the nuisance.

This Saturday my radiator failed, creating the same dreaded milkshake you have described. After installing a new radiator and having the tranny and engine flushed, the truck is running again. My theory is the poor shift conditions are caused by abnormally elevated fluid pressures. Perhaps this is caused by a faulty TCM or valve body? But why in four different transmissions? Could elevated fluid pressures have caused a failure in the tranny cooler?

All help is appreciated.

Thanks,

JUS