2nd Transmission Cooler

[Craigerz]

Thank for the help. So is everyone for skipping the radiator?

 

[Dono]

I'd keep the radiator if it were me. Over in the transmission section at the Yellow Bullet there are some serious transmission guys, and they say to keep it. They say the thermal transfer of two liquids is far superior to liquid to air.

Here's a thread, it still kinda leaves it as a 60/40 kinda thing.
Pros and Cons to running two trans coolers in series - Yellow Bullet Forums

 

[traveler]

I bypassed the radiator on mine because the lines didn't fit on my new radiator that was supposed to be a "direct bolt in". That said, I havent had any trouble with overheating or running cool. In fact it runs cooler without the radiator. Of course I live in the Phoenix area and dont need any extra help warming the transmission up.

 

[Turdle]

I also bypassed the radiator.

 

[Dono]

Its interesting, as everyone has an opinion. the idea of a trans cooler is to help warm up the trans oil faster, then keep the temp lower when hot. Traveler has data saying that the trans cooler is a negative on the cooling side. I'd go with the real world data here.

 

[traveler]

I'm sure that in the absence of a larger more effective cooler, the radiator does help cool the transmsission. However, I'd been running both the cooler and the OEM radiator prior to installing the new bigger radiator. The transmission cooled well, but it did run warmer than it does now without the radiator.

 

[CDW6212R]

Modern vehicles have coolant temps above 200*, which is bad for a transmission. These older Fords usually run coolant in the 190's, rarely a person chooses a 180 T'stat and has it below 190.

I couldn't get a useful answer about what an ideal ATF fluid should be, but I think it's between 120* and 150* or so. So aiming for that is tough given the radiator ATF path, and typical Winter or Summer outside temps.

I will make an attempt to install a thermostat device in my trans line. If it works to install a marine T'stat "pill" into an oil thermostatic bypass adapter, than I can keep ATF temps close to the 145* range, where the T'stat will open. If that works, then anyone can choose to skip the radiator, and maximize the cooler sizing, still ending up with predictable ATF temps.

 

[Craigerz]

Well my cooler idea got put on hold for awhile after my last fiasco. But ended up at the yard this morning and found a cooler off of a Sport Trac so I snagged it.

Now I just have 2 OEM coolers and bypassed the radiator. The mounting bracket is a little different so it sits up about 2 inches higher so it doesn’t have the symmetrical look I was hoping for.

 

[BUXTER]

Doing this now as part of Water Pump job - I've always believed in deleting old Rad Coolers because when these Plastic Ended Rads fail they can take out a perfectly good Trans - Now yes if u are up North u might want a Cooler Bypass with Thermostat, plenty of them around.

 

[BUXTER]

The key is to not increase fluid resistance, Dono is very correct. The way to do it is to not run anything else in series. Either replace the medium sized cooler with a much larger one, or add something and split the flow properly. Run everything in parallel, that way the flow is split, the resistance is reduced or left the same.

Stock on mine Coolers are in Series... Fluid runs thru one Cooler then thru the other cooler then back to Tranny - I wanna say Fluid to Coolers comes fm Torque Converter but its been a while since I rebuilt my 4r70w so it may the other way around - Personally I'm gonna delete lower hard line fm Rad (that ends up in hose at Air Cooler anyway) & replace it with short Hose Jumper fm existing Air Cooler to the new one - Upper Hard Line will get tweaked w/ Tubing Bender & run to Hose to new Air Cooler - & I deleted Rad Cooler for 1 Air Cooler just tucked above air dam w/ no fan on my 96 MKVIII 4r70w rebuild 70K miles ago w/zero probs in sunny SC but no it does NOT have a Tow Hitch on it ~! - IMO Rad Cooler is actually a Fluid WARMER - Keep in mind some peeps don't re-measure for 4r70w Thrust Bearing at rebuild as required... they just slam in the old color coded shim.