Coolant & Tranny fluid mixing? overflowing?
 

i wasnt aware this was even possible. noticed a large puddle under my rig last night and all over the undercarrige. it was red and somewhat oily. i tracked it down and found it overflowing from the coolant resevior tank next to the rad. took it to the dealership and they diagnosed it telling me that the rad broke and is mixing tranny fluid with coolant. tranny seemed to be shifting fine and the motor wasnt over heating.

sounds like the in-radiator transmission cooler let go......

should there be anything other than the tranny and coolant system i should pay special attention to now that this has happened? they are going to flush the motor and tranny twice to make sure they get it all out and replace the rad

just keep checking a few times a week to make sure you have no milkshake type fluid. damn that sucks thats some expensive . damn glad i own a tacoma

got the bill last night :( just under $1100. replaced the rad, flush & filled the tranny fluid twice, flush and fill the cooling system twice, flush and fill the diffs, unseize parking brakes, and cleaned my engine bay and undercarrige

i have been checking the oil.... no milkshakes

ouch... whats the specs on the runner? mileage, age

00 4Runner ltd v6 cali spec, a little over 100k

This is coming up really often now. Seems like a very very common problem which is showing its ugly head.

Did you have an OEM rad? and what fluid were you running?

yeah how often did you change the coolant and what kind of coolant did you have in there... toyota coolant can get very acidic if left in there too long. its great stuff but can become corrosive in extended periods. a master tech told me this from one of my local yota shops....granted it seems like there is a weak spot on the 4 runner rads which sucks for you guys bc thats an expensive mess to deal with and could lead to larger issues.... glad we dont see this in tacos :banger:

i have a 97, is there a way to bypass the trans cooler from the radiator to a separate cooler in like the front of the radiatior or something? i dont want that to happen.

I recently bought it and don't know too much about the history of it. But the rad looked oem. The fluid was a redish color but that could have been from the tranny fluid mixing in.

toyota did use coolant that was red once. i bought some from a toyota dealer. looks similar to tranny fluid. and coolant is kinda has a slight thickness to it.

if u check the tranny dipstick and u see just tranny oil, not a milky mix or anything watery. i say just replace the radiator if it's cracked and u should be fine.

if u wanna be safe and it's due for tranny flush anyways, just flush the tranny fuild at a mr transmission or something. change the tranny filter too.

i personally have never seen that trany cooling pipe inside the radiator ever go bad in any car i've ever worked on at the shop. even old wrecked cars. so might wanna check tranny fuild first before trusting what the dealer has to say

if you use some search terms like tranny with milkshake and strawberry you will get many threads regarding this issue. Mostly on 99/00 4Runners.

Yes, I've done that.

This just happened to me, and I did the exact thing the dealership did for you. I replaced my rad on my own and drained the fluid immediately, but i had the dealer do the power flush of my tranny twice ($400) and my coolant system once ($120~) Seems to be fine after a few thousand miles so far. My new coolant is Red, an I freaked out when checking it and called my service writer because it was green before and i thought it mixed again.

:2000 SR5 V6 4WD 172kmi:

The deal with the coolant mixing with the transfluid is that the coolant can separate the internal friction disks in your tranny from their backing plate therefore creating slippage and trans failure. Be sure to keep an eye on it. every 500 miles or so, leave it running and pull the trans dipstick and see if there is any metallic looking debris. you will have some just from wear an tear, but it should remain red for a long time. If it starts to turn brown and or flakey quickly, get on the search for a new trans.

MY service writer says that this happens to about 10% of the T4R's out there. (keep in mind, its one dealer, and cars are sold, traded, relocated...) He didn't denote age or milage, but I would be interested to see if there is some sort of pattern to this, so current and future T4R owners know what to expect, and may prevent $thousands of repair bills by changing the radiator every 8 years.

care to elaborate?

I already did here:
https://www.yotatech.com/forums/f2/b...cooler-126953/