There was a long thread some time back on the Derale 1/2" stat vs the 3/8" stat. Seems the 3/8 one is too restrictive. I want to change mime from the 3/8 to the 1/2". Anyone running the 1/2" one? Need to know what all I will need, fittings etc. And I don't know if I'll be able to get the hoses off those barbs, may have to cut and splice.


wish I could find that thread

 

Found the thread https://www.ford-trucks.com/forums/1...tallation.html but it looks like the efforts to find any differences between the 3/8 and the 1/2 are inconclusive. Both units claim the same flow rate yet at least one person reported lower towing temps with the 1/2". Not sure what to do yet, my temps are reaching 200-205 towing a light load (small boat & gear) in ambients of 100+. I know that's not terrible but I wouldn't mind seeing it closer to 180-190.

 

Those thermostats will raise the temp faster by bypassing the cooler. If yiu want a lower temp the 6.0l cooler like you have is best. I'm pretty sure your temps are fine where they are.

When is the last time the fluid was changed? What about the filter? What tune are you running while towing?

 

If the OP has the same problem I do, the TFT is too cold in the winter without a thermostat. I looked at getting a Derale, then I read about the TFT temps going too high after install. I'd like to know if I can get my temps up in the winter without skyrocketing my temps in the summer.

I have the HD4R100 with the stock cooler, which runs considerably cooler than the temps I have seen on the 4R100 data. The highest temp I've seen was 195 degrees up a steep grade on a 108 degree F day - in traffic. These temps were taken with an external gauge (before I sold it), Torque, and AE.

 

I also recall that Mark K said that the MIN temperature is somewhere around 165-175°F, IIRC. Get lower than that, and the fluid viscosity becomes a problem inside the tranny. Point is to not go too far on the low end, either.

 

I used the 1/2" Derale when I did the 6.0 cooler. Also installed the 1/2" Magnafine filter as well. Made the transition from 3/8 to 1/2 inch much easier and cleaner, only had to use one 3/8 to 1/2 barb/barb fitting. No issues with temps, most that I have seen is ~200* towing 11-12K on 7-8% grades in 100+ weather. Also warms up in winter but it takes a while as I have the in-radiator cooler as well.
And yes, form my trial fitting of things you will most likely need to cut the hose off of the barb fittings, they hold really tight. Hose clamps are probably overkill on them, but I wouldn't run without them just the same.

 

I did the same as hydro man, 3/8 to 1/2. The most I have seen my temps now is 200* which is just fine. You want your temps at a minimum of 180* to help burn off moisture in the tranny. Before I added the derale my temps wouldn't go above 140* then I added the 3/8 derale and temps were pushing 225* now I'm a happy camper with 180-200* with the 1/2 derale.

Yes you will have to cut the hose off because that barb just won't let go of the hose.

Also make sure you don't over tighten the brass fittings. I did on one of mine and over time the fitting split and had gusher of tranny fluid on my driveway.

 

Tranny has 50K on it, did the flush at 132K, swapped out 8 quarts at 145K and 8 more at 160K (last week). She gets a fresh filter every year (external spin on) No tunes, stock truck. Before the Derale I couldn't get over 170 at the hottest, now I see 190-200 in cold weather and 205 in hot weather. She even gets to 200 not towing anything in the winter on long grades at 85 MPH. I know it's probably fine, just a little worried about those hot mountain passes this summer.

 

I have some questions...

Any updates on people using the 1/2" derale thermostat?...Everybody still happy with them, any issues?
Is it worth adding a trans filters the thermostat? I'm concerned about negative effects using the thermostat AND a filter (magnefine or spin-on) as far as line/fluid pressure?


I am adding. 6.0 cooler soon and am planning to do the thermostat as well. Thinking I'll add a magnefine until I have the funds for a dieselsite external filter kit.

My new to me truck has 110k. All stock. Looking at previous receipts it had a valve assembly replaced at 100k bc it was having shifting issues and wouldn't go into reverse.

No issues now, shifts smooth. I rarely tow, mostly daily driving, so I want those tranny temps getting up there they need to be. When I do tow Its around 12k.
Just interested in doing anything I can to extend the life and invest in it's reliability where I can.

 

I put in my 6.0 cooler earlier this summer (June) with the 1/2" Derale. Not to put words in Mark's mouth but he said that 170F is the sweet spot for TFT and you should maintain above 150F to keep moisture out of the slushbox. Mine gets up to temp pretty quick and has not seen over 200F.

In a slight tactical miscalculation I plumbed it after the in-tank cooler and still have to correct that and put it before.

I've been very happy with my setup even with my installation error.

I had to change some routing when installing and there was no way to get the hose off the barb connections without slicing the lines.

I used the Derale 25792 unit (https://www.amazon.com/Derale-25792-.../dp/B004XOQ9BS).
I got 1/2" and 3/8" transmission fluid lines from the auto parts store as well as my stainless steel hose clamps. Depending on how you want to route it will depend on how much you need.
My barb fittings I got from Home Depot (3/8" to 1/2" and the NPT fittings for the thermostat). I had two 1/2" and two 3/8" fittings on the thermostat but I will have to go to a 3rd 3/8" fitting to correct my error. This will also require a 3/8" to 1/2" barb fitting to go after the in-tank cooler to upsize to the 1/2" line required by the 6.0 cooler. When I finally finish this it will go something like this:

3/8" from the transmission to the supply inlet of the thermostat
3/8" from the supply outlet of the thermostat to the in-tank cooler (for those that have one)
3/8" out of the in-tank cooler to a 3/8" to 1/2" barb to the 1/2" inlet to the 6.0 cooler
1/2" from the outlet of the 6.0 cooler to the return inlet of the thermostat (I installed my 1/2" Magnefine filter in this section)
3/8" from the return outlet of the thermostat to the transmission

That's my plan when I get around to re-routing the lines. Some people mount the thermostat near the fender but I chose to install it on the crossbar under the radiator. I will eventually fashion a steel plate to cover it to act as a deflector against debris. Always something to do...

 

Here's a trick I just recently learned about removing hoses from barb connectors without damaging the barbs, and it even works on PushLok fittings...

Use a soldering iron with a flat blade-type tip to simply melt/cut the hose off the barb. Be patient. It takes a few minutes, but the results are really wonderful and you don't end up wasting a fitting.

 

Thanks for the tip!

I usually have success using a razor blade and make a bunch of cuts with light pressure until I get most of the way through the hose and can slide it off without damaging the fitting.

 

I did replace my Derale 3/8" thermostat with the 1/2" one and I didn't notice any difference in temps.

 

Thanks Gents! That helps a lot!
Ordered a 1/2" thermostat and magnefine filter. Should get here Friday.

I got a low mile (88k) 6.0 tranny cooler off a wrecked truck that looks like it's in good shape. The guy I got it from buys trucks at auction to use parts he needs and then sells the rest. He said the tranny was "good" but you never know. I'll be flushing that thing thoroughly with some Dr. Tranny Kooler Klean since you never know. I was thinking I'd flush it into a clean container so I can get my eyes and any gunk that comes out. Hoping to ease my concerns of using a used cooler.

If anybody has any tips for flushing a cooler let me know.

 

Flushing a trans cooler is a real crap shoot. I did it and was lucky, but many have not been as the design of the cooler is not user friendly to flushing. The passages are very convulated and do not flush well.