Thread: 4t65e-hd trans cooler?

Originally Posted by Cordless

So is it better to go stand alone or in line with factory cooler?

Yes. LOL

This one can be argued both ways. I chose stand alone.....
1) I don't feel it gets cold enough here to be of concern.
2) When I see what a piss poor job the rad does at cooling the tranny, why would I want it to continue in its piss poor way.
3) Added bonus is that when the rad fails and tries to put coolant in the tranny, it will fail at that too. LOL

That usually happens when the coolant system is not maintained for example people run straight water for extended periods of time or never change coolant that has become corrosive.

If you have a local U-pull-it junkyard, you can get a stacked plate style cooler off of a ford explorer w/ towing package for $10. Then just buy some rubber transmission line and some double-sided barbed fittings and some clamps to splice into your factory lines. Very cheap, and effective. Installed standalone. Has built-in low-temp bypass function, and has kept my transmission cool even on hot days going up/down mountains.

^ This.

170-180* I think is ideal, but as long as I can keep it under 200* I will be happy.

I have driven my GP for over 100,000 miles as stated previously with 2 Long (aka Dana) double stack 18,000 GVW (total GVW is 36,000 GVW!) with built in temperature control (car is currently at 190K miles). Both coolers are stand alone and used all year round in temps >100 degrees and less <0 degrees with no issues and no cardboard/material blocking the coolers in the winter. I have used these Long /Dana coolers in multiple cars I own as stand alone coolers...I just installed the Long 28,000 GVW cooler in my 2008 Chrysler 300 (stand Alone) again. I highly recommend LONG:

http://www.ebay.com/itm/LPD4589-TRU-...-/261294060243

You decide the GVW rating but I would go 24-28,000 GVW...the GP is at 36,000

As far as fluid temperature goes, I would recommend NO HIGHER than 170 as an average temp...with that number probably marginal for best tranny longevity. My transmissions generally run about 145 in summer with the Long coolers and 125 in the winter. Here is just 1 quote from transmission experts I found:

What is the best fluid temperature for an automatic transmission?

"If you could keep your fluid at 140°F that would be ideal. Most transmission fluid works best at this temperature. In actual application keeping the temperature this low is difficult. Try to keep your fluid temp below 190°F. If it gets to 230°F or higher for any period of time you should start looking for a place to pull over and park for a while".

Just an FYI-Many domestic heavy duty pickup truck with Diesel engines and factory stand alone tranny coolers routinely run tranny fluid temperatures in cold weather highway driving of 115-120 degrees....