Help! Transmission overheated, blown.
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From: Jax
Help! Transmission overheated, blown. I have discovered that because I had a bad radiator cap that wasn't sealing, there was really no pressure in there, and also water leaked out. But instead of seeing the usual engine overheat, my TRANSMISSION was overheating first, several times, leading to blown tranny.
I had asked the people in tire kingdom to make sure the coolant system was 100% because i didn't want any problems with overheating the engine or transmission.
After they did all this work for $1000, they never replaced the cap. What I saw was the reservoir was always full, and not moving. I didn't realize that the water in the radiator was going down.
Does the transmission fluid line go into the TOP of the radiator?? Why was the transmission overheating before the engine would?
Since I've replaced the transmission and the radiator cap, im fine. but pissed. I dont have the money for this and had to put it on credit. Since I've replaced the cap, the water in the reservoir fluctuates properly.
Also, tire kingdom is claiming there is no way to inspect a radiator cap other than visual. Is this true?
I'm out 1100 for a transmission because it kept overheating. Im sorry but they should cover this loss. Pissed. I had no idea what was happening because the reservoir was full.
I had asked the people in tire kingdom to make sure the coolant system was 100% because i didn't want any problems with overheating the engine or transmission.
After they did all this work for $1000, they never replaced the cap. What I saw was the reservoir was always full, and not moving. I didn't realize that the water in the radiator was going down.
Does the transmission fluid line go into the TOP of the radiator?? Why was the transmission overheating before the engine would?
Since I've replaced the transmission and the radiator cap, im fine. but pissed. I dont have the money for this and had to put it on credit. Since I've replaced the cap, the water in the reservoir fluctuates properly.
Also, tire kingdom is claiming there is no way to inspect a radiator cap other than visual. Is this true?
I'm out 1100 for a transmission because it kept overheating. Im sorry but they should cover this loss. Pissed. I had no idea what was happening because the reservoir was full.
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From: Jax
also: After I had the transmission replaced, a few days later, I noticed that the fluid in the transmission was down 3 quarts. WHAT THE HELL. it was full when I left the transmission place, and there are no leaks. Anyone a transmission guy here? Wish Poppy was still alive he was a transmission man for 20 years. 
TECH Junkie
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From: Poplarville, MS
Yes radiator caps cap be tested. The way this is done is by screwing the cap on to an adaptor and then pressure testing it with the same tool that you would pressure test the cooling system with.
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From: Jax
THANK YOU. I THINK I GOT THEM. HE ADMITTED THEY DIDN"T TEST IT, but it's because he said "there is no way to test a radiator cap, only visual"....To which I replied "In a 16 year old car that you've just replaced the entire coolant system (except heater core) why wouldn't you change out the $5 cap? It cost me 1100 because he didn't change it out.
TECH Junkie
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From: Poplarville, MS
You didn’t state what vehicle you have. Some vehicles are very hard to get an accurate reading of the fluid level after just having fluid added. I always go back and recheck an hour later.
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From: Jax
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If they replaced the entire coolant system for $1,000 but reused the ancient radiator cap, that's a shop I would tell people to stay away from.
It's really hard to find an honest mechanic who does good work. It seems like they'll either be cheap but do bad work, or do good work but charge waaaaay more labor than you know it took them. I recently had a shop charge me $150 labor for a 20-30 minute job, but said it took 1.5 hours. I asked the specific mechanic at the shop who did it if he had a lot of problems or something but he said it was really easy and went smoothly.
It's really hard to find an honest mechanic who does good work. It seems like they'll either be cheap but do bad work, or do good work but charge waaaaay more labor than you know it took them. I recently had a shop charge me $150 labor for a 20-30 minute job, but said it took 1.5 hours. I asked the specific mechanic at the shop who did it if he had a lot of problems or something but he said it was really easy and went smoothly.
Last edited by coryforsenate; Apr 10, 2015 at 02:56 PM.
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Teching In
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From: Jax
I am probably not going to be able to prove it was a bad cap that caused overheating issues, then causing my transm to overheat and blow
Back to transmissions, I'm curious about how the transmission cooler inside the radiator works.
Is the transmission fluid temperature not affected by the airflow through the radiator? I would think there would be some cooling by airflow, and since the coolant isn't circulating through the engine the coolant wouldn't be heating up the transmission fluid like it would during normal operation since the coolant thermostat typically holds it to about 190F. It seems like if the coolant wasn't circulating, the radiator would basically be acting as an external transmission cooler.
And if the transmission overheated before the engine, that seems odd. The transmission doesn't generate a lot of heat unless you're shifting constantly, like in congested traffic. If the coolant wasn't circulating, the engine should exceed normal operating temperature very quickly.
Is the transmission fluid temperature not affected by the airflow through the radiator? I would think there would be some cooling by airflow, and since the coolant isn't circulating through the engine the coolant wouldn't be heating up the transmission fluid like it would during normal operation since the coolant thermostat typically holds it to about 190F. It seems like if the coolant wasn't circulating, the radiator would basically be acting as an external transmission cooler.
And if the transmission overheated before the engine, that seems odd. The transmission doesn't generate a lot of heat unless you're shifting constantly, like in congested traffic. If the coolant wasn't circulating, the engine should exceed normal operating temperature very quickly.
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From: Ann Arbor, MI
The stock trans cooler is just a very short pipe within the radiator and it expects to be covered in radiator fluid for liquid-to-liquid cooling. Obviously it will not cool below the engine coolant temperature, but it is generally placed on the cooler side of the radiator.
When there is no coolant in the radiator, there will be very little cooling of the trans fluid.
I don't have the experience to even guess at how much cooling the trans needs in a stock V6 engine, but perhaps it does need what the stock cooler provides.
Cory, I agree that I would expect the engine to overheat first.
OP: Keep an eye on the trans fluid. I assume you know it needs to be checked with the engine running. If the fluid level goes down, but you see no ATF leaks, it could be leaking into the engine coolant within a defective radiator. This will kill the trans very quickly .
When there is no coolant in the radiator, there will be very little cooling of the trans fluid.
I don't have the experience to even guess at how much cooling the trans needs in a stock V6 engine, but perhaps it does need what the stock cooler provides.
Cory, I agree that I would expect the engine to overheat first.
OP: Keep an eye on the trans fluid. I assume you know it needs to be checked with the engine running. If the fluid level goes down, but you see no ATF leaks, it could be leaking into the engine coolant within a defective radiator. This will kill the trans very quickly .