Transmission cooler leak = bad!

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My brother recently got a 2002 Toyota Tundra 4.7 with 200K miles in December. It needed (and still does) some work done but nothing major that affected drivability. Today he informed me that his transmission cooler blew a line and quickly puked transmission fluid into the radiator which went all though the cooling system. He said that he stopped driving it shortly after but did experience slipping when driving away from a stop sign, I'm assuming it puked too much ATF causing low pressure. It was towed to the shop and hopefully will know more on Monday. They told him the transmission and cooling system would need to be flushed and I'm not sure what else. I feel bad for him since he just got the truck not even a couple months ago. He still has his first truck, a 1991 Ford Ranger with 380K miles on it that he can drive for the time being but it just stinks that he will have to sink this money into the Toyota. Hopefully it wont cost too much as he plans on replacing the timing belt (unknown last replacement).
 
This is relatively common for Tundras (and Tacomas.) Flushing the coolant and ATF ASAP may save it, but it's a cràp shoot.

Google for "Tundra pink milkshake".

It's generally recommended to bypass the radiator's transmission cooler entirely and install an aftermarket transmission cooler on these things.
 
A 15 year old 200,000 mile vehicle usually needs lots of replacement and repair items. Last summer I replace all the PS hoses on the wife's 2002 F250. This year or next year the coolant hoses
 
Originally Posted By: mooferz
This is relatively common for Tundras (and Tacomas.) Flushing the coolant and ATF ASAP may save it, but it's a cràp shoot.

Google for "Tundra pink milkshake".

It's generally recommended to bypass the radiator's transmission cooler entirely and install an aftermarket transmission cooler on these things.


I hope nothing was damaged, that would be awful.
 
Originally Posted By: CT8
A 15 year old 200,000 mile vehicle usually needs lots of replacement and repair items.


Yep. Unless the previous owner was obsessive (like you?!) about it at that age and mileage upkeep was probably being ignored. It sucks but really shouldn't be a surprise. Hopefully water didn't get in the tranny but don't bet on it. I've heard of the strawberry milkshake of death (SMOD) in 4.0L Nissans, but not Toyotas. It kills the Nissan tranny most of the time.
 
I don't think it takes much water/coolant to destroy the clutch packs in an auto tranny.
 
Originally Posted By: dishdude
I don't think it takes much water/coolant to destroy the clutch packs in an auto tranny.


Probably not, but wouldn't the transmission pump pump out fluid keeping the coolant from entering the transmission? My brother said the transmission fluid overloaded the cooling system and ended up coming out of the overflow tank.
 
Originally Posted By: gregk24
Originally Posted By: dishdude
I don't think it takes much water/coolant to destroy the clutch packs in an auto tranny.


Probably not, but wouldn't the transmission pump pump out fluid keeping the coolant from entering the transmission? My brother said the transmission fluid overloaded the cooling system and ended up coming out of the overflow tank.


The cooling system is pressurized so logically it probably pushed some coolant into the tranny return line before it became apparent.
 
Common failure point on many cars. On my Ford Falcon, I bypassed the factory trans cooler and run an air to air cooler. No chance of cross contamination of fluids then if a leak occurs. This is the route I'd suggest your brother takes too.

He's lucky, it sounds like the trans didn't ingest any coolant, which they never seem to recover from. New radiator, flush the cooling system, aftermarket air to air transmission cooler, and hopefully it'll be good as new!
 
Besides the transmission slipping, was there any other indication that the cooler failed?

I would remove the thermostat and do many many distilled water flushes. As for the ATF and assuming it takes T-IV, I would flush it with a cheap DexIII then do 1 or 2 "good" flushes with the correct fluid then check it weekly and change as needed.
 
Is the transmission fluid like Pepto-Bismol? If so time to save for a transmission rebuild the unit is doomed to fail its just a matter of time. Flushing it will not stop the clutch disintegration, the glue used to hold the clutch material to the steel plates in the transmission and TC is already compromised and failing.
If its still red he has a chance, a new radiator and cooling system flush is the least of his problems, they are minor problems that are easily remedied.
 
Originally Posted By: Trav
Is the transmission fluid like Pepto-Bismol? If so time to save for a transmission rebuild the unit is doomed to fail its just a matter of time. Flushing it will not stop the clutch disintegration, the glue used to hold the clutch material to the steel plates in the transmission and TC is already compromised and failing.
If its still red he has a chance, a new radiator and cooling system flush is the least of his problems, they are minor problems that are easily remedied.


It was towed to the shop shortly after the failure, so I never had a chance to look at it.
 
This sucks. I knew there was a reason to like manual transmissions. Also the current parts store radiator options dont instill confidence that it wouldnt happen again.
 
I wonder if the in-rad ATF cooler goes bad due to neglected coolant or corrosion in the fittings?
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Not my pics but I wish I took pics when I dissected the old radiator from my 2001 Tundra. Wanted to see if there is any imminent failure. Only thing failed was the upper rad tank.
 
Sad to say, he got word today that the transmission is shot. I feel bad for him since he just got it a few months ago.
 
Originally Posted By: gregk24
Sad to say, he got word today that the transmission is shot. I feel bad for him since he just got it a few months ago.
Wow, both brothers have dead transmissions this past week?

Have you guys driven it and checked the level? Shop might just want to sell a transmisison.
 
Originally Posted By: Nick1994
Originally Posted By: gregk24
Sad to say, he got word today that the transmission is shot. I feel bad for him since he just got it a few months ago.
Wow, both brothers have dead transmissions this past week?

Have you guys driven it and checked the level? Shop might just want to sell a transmisison.


No, we haven't. I know it was at the correct level when he got the truck 3 months ago, and as far as I know it didn't leak. I am guessing at others suggested the coolant got in the transmission fluid and messed up the clutch packs, that or the fluid got to low when the line burst and ended up frying the clutch packs, or a combination of both.
 
this is definitely not toyota specific. happens on a lot of makes. Stinks that it happened just after he got it.

The aisin transmission in that model has a thermostatically controlled cooler loop. If you bypass the radiator, which can help warm the transmission, it won't warm up as quickly but certainly will not be overcooled due to the handy thermostat. I hope he can source a good deal on a replacement trans. We are very happy with our 06 - they are good, honest trucks.

-m
 
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