What Happened to Tamerlyn's Transmission?

Dear Car Talk

Dear Car Talk | Apr 24, 2014

Dear Tom and Ray:

What would make a transmission line blow out?

-- Tamerlyn

TOM: Sorry, Tamerlyn. I take it you've had a catastrophic event in your life recently.

RAY: Would congratulations on your new transmission be in order? I hope not.

TOM: Age is the most common culprit in transmission line failure. Those lines are made of steel and rubber; they're steel with rubber sections at the end where they connect to the radiator.

RAY: The lines carry the transmission fluid, which is about 450 degrees Fahrenheit, to the radiator, which is a mere 250 F, so the fluid can be cooled before being sent back to the transmission.

TOM: And those lines operate under pretty high pressure. But they're really tough, too. The rubber has to get pretty old and worn out before it fails. And normally, if you get your car serviced regularly, your mechanic will spot a questionable transmission line before it breaks.

RAY: It's possible that a problem inside the transmission caused the pressure to increase. That would make a line more likely to blow out, since it's the weakest link the system.

TOM: But you probably would have seen the "check engine" light come on. And you would have noticed the transmission behaving differently when you drove (before the line blew out ... we know it behaved differently after that).

RAY: So I'm assuming the culprit is old age and lack of a regular mechanic, Tamerlyn. You didn't give us your address; otherwise, we would have sent flowers.

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