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

harner

harner

New member
Hey all,

I'm pretty beat from working on the car all day. Did an oil change, plugs/wires, and swapped my '98 GT radiator to a '02 GTP radiator. I'm collecting parts for a top swap and figured I'd get a used working GTP radiator for now. My GT rad cracked on the return side while in traffic about 2 months ago.

So, I just need to install the tranny lines, install the new lower/upper rad lines, add coolant, and then I can have some rest.

I have done research on here and Google. Found some great threads and not sure what direction I want to go or what I really need. So, here goes.

The top trans line (I believe it's the return) seems to be smaller and fits in the fitting on the Rad no problem. The lower trans line doesn't fit. The connector seems too big. The return line fits into both fittings with no problem.

- Now, since '98 is an oddball that supposedly has a weird line which threads at the trans and clicks on the Rad, I don't know if I can upgrade the whole line to say an '02 GTP feeder line. Does the '02 GTP line bolt in at the trans and click in at the rad? I read that it's click at both.
- I assume I can't swap fittings on the radiator because they don't seem to budge. I found pictures of the fittings, so maybe they are loctited one or something, but definitely not budging with my line wrenches.
- What are you thoughts on just running an aux cooler and getting rid of this headache entirely? What about hacking apart a new '02 GTP feeder line and connecting the old and new line with some rubber hose?

Thank you.
 


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!
 
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.
 


Our operating temperature for the 4T65 is 160-220F. You can't hit 350F as limp mode comes in around 260F iirc.

Running a 4T65 as cool or cooler than 120-135F will mean that it never gets to operating temp and could end up with condensation etc not being heated out. Therefore causing water contamination inside the trans and more damage than heat.

The size of the trans cooler in the radiator end cap is pretty small. In most of the areas we drive, this should be adequate. If you live in Arizona or the mountains it would likely be a good idea to add a cooler for the hot weather.

A fresh rebuilt trans typically runs cool anyhow.
 
Very true.

That being said, I bet there are 1,000,000 transmissions that die by heat for every 1 that dies by cold.
 
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.
 
This thread is way out of control. I'm not going to run a cooler on this car just for the sake of keeping the trans temps down. I know the pro's/cons and run them on some of my other GM cars that actually have heat issues, where running a cooler prolongs their life. I might when I have a built/rebuilt trans down the road and then I'll consider one for the sake of cooling. Right now, the trans has issues but it's drivable. My issue was the cooler line and a work around for it. After sleeping on it, I decided what route to go.

I am buying a used feeder line off a newer GP and will be hacking it up and connecting it via rubber hose to my existing line.
 


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