Thread: Need help on cooler line issue - upgrading to a GTP trans

Do yourself a favor and run the trans fluid through the biggest double stack (not a tube and fin) cooler that you can fit in front of the condenser in the grille! There are many benefits to this approach:

1. Heat kills the tranny-running the trans fluid through the radiator cooler severely limits the temp the fluid can be reduced to.
2. Trans fluid is VERY hot and will make the radiator work harder cooling the engine on hot days
3. No trans fluid contamination from coolant leaking into the trans from broken trans radiator lines.
4. Cool trans fluid will last MUCH longer than radiator cooled trans fluid. My trans fluid runs about 125-135 degrees on hot days, less in cold weather.

I run dual 18,000 GVW double stack Long coolers in the grille of my GP outside of the radiator now for about 35,000 miles and have had zero issues in very hot or very cold weather. Trans shifts perfect.

Hope that helps!

by that logic you need an engine oil cooler so your oil lasts longer right?

Completely different.

What friction material is there in an engine?

That being said, oil coolers for the engine do indeed exist and can provide benefit.

Explain to me how worn out clutches, stripped splines, broken chains, enlarged vss reluctor mounting holes and clogged valve bodies/ solenoids are heat related.

From google:

"Overheating is one of the leading causes to transmission failure. A transmission should run at about 175-200 degrees Fahrenheit. It is not uncommon for the transmission to exceed temperatures of 350 degrees. Overheating the transmission can cause severe damage to the internal parts of your transmission. It can cause warpage to metal parts, degradation of fluid, sticky valves, and the melting of seals. Dexron-Mercon III is designed to last up to 100,000 miles. Any 5 degree increase in fluid temperature will reduce fluid’s life by 5,000 miles. The parts inside your transmission are categorized into two categories: soft parts and hard parts. The hard parts are, like described, hard. They are generally made of hard steel or aluminum. For example, a drum or a planet is a hard part. The soft parts of a transmission are made up of the rubber seals, gaskets, and clutches.

There are a few common ways to overheat your transmission. Listed are the most common:

• Speeds over 90 mph
• Towing a heavy load
• Stop and go traffic in hot weather
• Racing
• Repeatedly putting a car in drive and reverse to get unstuck from mud or snow
• Running your vehicle in 4WD generates more heat than normal use.
• Neglecting scheduled services

As you can imagine, a lot heat is created inside of a transmission with all that work and shifting it does when you use it. Your transmission uses the radiator to help maintain a safe constant operating temperature, and the fluid to cool and lubricate all those moving parts inside your transmission. Transmission fluid begins to cook at 200 degrees. After it cooks, it carmalizes and then burns. This is one reason it is crucial to change your transmission fluid regularly"


Hot ATF is less viscous and can varnish. This can cause wear of your friction material that can then clog your internal valving. Also, as mentioned above, you can warp internal parts etc.

Very true.

That being said, I bet there are 1,000,000 transmissions that die by heat for every 1 that dies by cold.

Tell me how 4t65e's die.

Mine died with a slipping forward band. Heat related? I doubt it.

My guess is that most transmissions die due to not changing the fluid regularly. What exacerbates this is heat as it shortens the ATF life.