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I'm having a transmission, and radiator problem

I'm having a transmission, and radiator problem with my 2001 Pontiac Montana Mini-Van. I just purchased this car from my neighbor and the first time on the highway my transmission fluid blew out the back of the car, smoking until I pulled the car over and cooled down. We flushed the transmission, replaced the seal, flushed the radiator (supposedly, I took it to a nearby garage, who are friends of the previous owner), changed the oil, replaced with a new pan gasket. When I and the seller went to pick it up, once again the radiator blew the large hose off (the one at the top right of the radiator when your facing it.) from the radiator. They are now trying to convince me that I need a new radiator. I don't believe that they flushed properly because there are still sign of a brown thick liquid inside the radiator, akin to a radiator stop leak. Any suggestions?

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If it built up enough pressure to blow a rad hose off the vehicle the problem is more apt to be a thermostat not opening as well as a rad cap that's not releasing pressure. There has to be a lot of pressure built up to blow off a hose. The system can put up with about 16lbs of pressure before the rad cap vent will blow of pressure if the cap is defective then it blows at the next weakest point . but the next question should be why is it building pressure. This happens when the system doesn't circulate properly usually from a thermostat not opening . so check thermostat and rad cap Hope this helps

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Sounds like the transmission cooler tank that is inside the radiator is cracked and leaking into the radiator it's self. (The Pressure from the cooling system will blow off a tail shaft seal)

Does the transmission fluid still look red? If not...This is your problem.

If both the transmission and radiator are contaminated.... this is an obvious sign of a trans cooler tank rupture. They should have suggested a new radiator before even letting you take the vehicle.

Because coolant is back flowing into the transmission, it will eventually lead to a transmission overhaul.

A new radiator, and flushing the transmission again should solve the problem.

I have worked in garages for years, and sometimes someone does not tighten a radiator hose all the way (it happens) and the hose blows off.

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