Radiator keeps taking my Transmission out

[newtek007]

2006 Chevy Tahoe LS 5.3 engine

Sooo.... been dealing with multiple transmission rebuilds since last June. Truck has 242,109 on it right now. Tranny last year started to go bad so I had a reputable local shop rebuild it. Couple months later the torque convertor went bad again. They replaced it. Couple months later, same thing happened along with another gear busting going up a mountain. Had to tow 100 miles back home. They rebuilt again and the same results. However..... this time when they opened it up the tranny fluid looked like stawberry mix fluid. They said the radiator tranny cooler had failed and dumped coolant into my tranny cooler lines. They would not cover it under warranty. I get it.... pissed, but I get it.

Took the tuck to AAMCO and had them rebuild it. No offense to the other company, but I wanted someone else to rebuilt.. just in case. Not gonna keep up with the same story, but the same scenario above has just happened again. This time though, AAMCO installed a new radiator and cooler lines so it is under warranty.

It is currently being rebuilt again. This will be the 2nd radiator AAMCO will install. We decided to bypass the radiator this time, as I don't tow a lot of stuff and quite frankly I am not gonna have the tranny die from coolant again.

My question is this.... is there something lurking and hiding in the coolant system that is causing the radiator cooler to fail and take the tranny out? Water temp has been spot-on and never any issues.

The radiator is the most replaced item on this truck with a grand total of 5 since I have owned it. Bought it with 125,000 on it. The other radiators just busted around the drivers side and leaked radiator fluid.

Any help with this would be great.

 

[OR VietVet]

The ONLY way trans fluid gets in to the radiator and coolant in the trans is because of a radiator trans cooler failure. What brand of radiators are you and Aamco using? This is a head scratcher. You would think that a reman trans and a new radiator fixes it all and you drive happily down the road. Freakin' weird mechanical problems!!!!!!!!!!!!

That's it, I can't take it! Now I am gonna worry about my 05 Z71. Never mind, I am gonna sell the rig and buy a bike and become a hippy here in Eugene, Or. Problem solved.

 

[exp500]

Could also be an extreme pressure problem from the trans. Blows a hole in cooler, then when truck shut off, backflow to trans. Shops almost never put guages on anymore. Many rebuilders now(dyno,test bench) their rebuilds,but only the better ones.
Keep updating findings.

 

[OR VietVet]

Could also be an extreme pressure problem from the trans. Blows a hole in cooler, then when truck shut off, backflow to trans. Shops almost never put guages on anymore. Many rebuilders now(dyno,test bench) their rebuilds,but only the better ones.
Keep updating findings.

Now there is a reason for the failure that is not caused by a faulty radiator. Something else causing the failure to happen is what needs to be looked at.

 

[exp500]

My friends 97 got 5 transmission rebuilds. None worked longer than 2 weeks. I asked him Why keep using that Core? I would have switched after 2nd.

 

[OR VietVet]

My friends 97 got 5 transmission rebuilds. None worked longer than 2 weeks. I asked him Why keep using that Core? I would have switched after 2nd.

Exactly.

 

[Bill 1960]

What was the source of those radiators? Probably not OEM.

I put an aftermarket radiator from a big name vendor in my project Jeep a few years ago. That Chinese POS leaked immediately after installation. I returned it and paid the price for OEM and haven’t touched it since.

 

[Rocket Man]

This is why my trans builder (Performabuilt) states in their install instructions to bypass the cooler in the radiator and use the supplied aftermarket cooler. I chose to install a new AC Delco radiator instead just to be sure the cooler in the radiator doesn’t fail. You must have got some cheap aftermarket radiators over the years. But since you bypassed it, you should install a Tru-Cool 40k cooler because high temps will kill a transmission as well.

 

[OR VietVet]

I never looked in to this because I did not regularly build transmissions in my shops. What is too high a temp for the trans? Just when it gets to red on the gauge? Lower temp for a prolonged period of time? Since I have my trans temp gauge, even when I am driving the crap out of my rig, has never exceeded 180 degrees.

 

[Jimmyy]

I had a chev Astro van went through 4 transmission in a year. The fix was to replace the ECU.