Ouch!... ok im changing my oem rad first thing tomorrow.
http://www.toyota-4runner.org/3rd-gen-t4rs/82033-3rd-gen-4runner-buyers-guide.html
Fixes/ How to avoid:
Except for regular coolant flushes as I mentioned before, there are two ways to really avoid a strawberry milkshake. The first is to just replace the radiator before anything happens; every 8 years is a good interval to set for replacement. The second way to avoid the milkshake is to install an external transmission cooler that is separate from the radiator. This removes the possibility of the milkshake ever happening as the radiator and coolant are removed from the equation. Or, if you’re wanting to really do it right, do both of these things. The new radiator will be about $150 (Koyo 1998A) and the external transmission cooler will be at least $60 (B&M 70268).