Bypass Radiator trans cooler??

Just street cruising, occasional burnouts, some spirited driving and traffic from time to time. I ordered a new radiator and it does not have the integrated trans cooler. Can I just use an auxiliary cooler and bypass the radiator?

I would either have to send the radiator back and spend another $100 to swap or buy an auxiliary cooler.

If the aftermarket cooler is a decent sized one, I don't see a problem at all doing that.

Yeah, no issues going with separate cooler . . . just go easy when things are not warmed up to operating temps . . . I had separate cooler on my Duster360 with 727, was like that for over 100k miles !

The "cooler" in the factory radiator performs one function. It maintains the trans fluid's temperature. When it's hot it cools it when it's cold it warms it up. Transmission do not like to run too hot OR too cold and too many don't realize that the "cooler" is also a "heater" when needed.

If you choose to run an additional, external cooler make sure it has a thermal bypass that will not allow it to cool the trans fluid when it's already too cold.

So, no, do not run just an external cooler.

While sniper is correct regarding temps and transmission fluid, given your location (Florida), I don't see an issue.

I had a factory trans cooler off a cop car that was as big as an AC condenser, took up the entire space in front of the radiator. From the factory, the fluid went thru the radiator first, then the cooler. When the trans cooler in the radiator failed, I ran just the auxiliary cooler. I ran the transmission this way for over 100K miles without issue.

I think the factory coolers have a thermal bypass valve to prevent over cooling.

Thanks for the replies, after speaking with a few of my car friends and your input I am confident I will be fine with just the cooler and bypassing the radiator. The bigger issue with my set up was the 22" radiator only allowed for a 15" fan with a shroud.

The 26 will allow a 18" fan that was the original to the engine.

The thermal by-pass is there for one purpose - get the fluid up to temperature as quick as possible.

Fuel economy first, then consistent shift quality next.

Cooling packages are so good now on factory cars and trucks and with lockup that it’s possible for fluid to run way to cold for much too long killing fuel economy. The by-pass speeds the heating up to prevents that.

With a non-lockup converter that’s not too likely for those in the sunbelt states (not too likely to stay cold).

In Super cold areas it’s possible for some fluids to gel in the aux cooler driving in ambients that are sub zero,
trans fluid with Paraffin based additives at -15F.

The T bypass was/is especially needed there.

Many people like me don't drive our muscle cars when its real cold out. I like to have the windows down when I drive my 63 because I enjoy it more like that so I don't drive it in very cold weather. Its usually at least 55 to 60 degree's out when I drive mine. And I have used only an aftermarket cooler mounted in front of my rad. I have been driving and racing mine like this since 2006 and its still working great and the fluid is a nice red color. In fact I just raced it about a week and a half ago and it still shifts perfect and still runs 10.70's and 10.80's all day as it has since I put this eng in in 2011. My point being since I don't drive in real cold weather its worked fine since 2006 with just an aftermarket cooler. Ron

Same here, on the few automatic equipped vehicles I have, I prefer to run just a remote cooler, esp after loosing 2 transmissions over the years to the internal radiator trans coolers rupturing and mixing h20/antifreeze in the tranny...

ONLY APPLICATIONS I would not have a ATF WARMER is on a racer that has a super hi stall converter in it or in a RV.

If you decide to use the external cooler only install a good, accurate, tranny temp gauge in the pan so you know what the actual trans fluid temps are
If it never gets above 160 F move it to a place that it will run from 160 to 240 F all the time
Dominic,Thumperdart, did what you doing when he went to a aluminum radiator in his BB Dart, he had a small three row cooler mounted in front of the radiator and the trans temps in the summer in Victorville, CA in the Mohave desert never got above 140 F when he was beating on the car street racing it in town
He moved so it was between the bumper and the radiator mounted horizontal to the street out of the main air flow and it ran from 160 to 220 F

Well I feel like the dimwits from "Barrys Speed shop" cutting and fabbing after paint and reassembly changing things that I should have done different in the first place.

Here is the 26" radiator in place, I need to fab up my shroud next and I am going to do my cam swap since all is out of the way.