I just bought my tranny cooler and i'll be intalling it soon after my gears go. I know some people install the new cooler in series with the stock cooler. now my question is what is the advantage to this? Why not just use the new one.
It used to be believed that keeping the stock radiator cooler in the chain allowed the fluid to heat up faster due to the coolant dumping heat toward the tranny cooler side, but that's a moot point, considering the tranny fluid hits operating temperature much sooner than the thermostat allows the hot coolant to circulate in to the radiator.
I did not include the stock cooler when I hooked up my aftermarket cooler. I was monitoring my Transmission Fluid Temperature (TFT) before the cooler and it would stay around 180*-200*. With just the aftermarket cooler, stays around 140*-160*. Good to go.
This is another of those fiercely debated issues. You'll find the same discussions on other vehicle message boards too. There are many arguments to the "in-line" configuration.
Some feel it's best to put the new cooler on the return line. That way, the stock cooler drops the temperature some, then the aftermarket cooler will drop it even more. The temps I got with just the aftermarket cooler show that you don't need to pre-cool it. A decent aftermarket cooler will do the job.
Some feel it's best to put the new cooler on the supply line. The thought here is that the stock cooler will bring the TFT closer to "the ideal" temp of 180*. Instead of supplying the transmission with 160* fluid, the stock cooler would raise it to 180*. I don't get that either. The transmission will do that, and then some. No need to pre-heat it.
There's also the belief that the stock cooler (being attached to the radiator) will pre-heat the fluid in the winter time. But in those freezing temperatures, the thermostat will be closed or just barely open. The coolant in the radiator won't be hot enough to pre-heat anything. Again, the transmission will heat up the fluid itself.
It's your call. If I had to do it all over again, I'd still go with just the aftermarket cooler. Nothing else.
To me, it depended on the final look of the install.
On my foxbody, I ran in series, because bulkpart.com had some nice looking plumbing & fittings, which made the installation look OEM. People who eliminate the radiator generally have plugs in the holes, and have either cut the tranny lines to run the hose around the front, or just have the lines hanging in the middle of nowhere with hose barbs in there.
Those kind of details matter to me.. maybe they don't to other people.
runing it in series is fine. or all by itself is fine as prophead did. just do what he did and monitor your trans temps. if they are staying under 180 then your good.