^ I really don't know the answer to that. My car was a manual car, so the radiator I removed didn't have these fittings. So I just have them capped off right now, but I am not sure if I actually lost a little cooling capacity with this A/T version radiator.

 

Ah, that explains it. I'm in the same boat, with capped off lines. I didn't realize the original radiators were different in that respect. Mine looks like it was replaced pretty recently.

 

I personally don't like the radiators with integrated trans cooling... all that happens is eventually the chamber will crack and you get radiator fluid in your transmission, and then bam you need a new transmission. it happens on the trucks and 4runners alot as well as other vehicles but it does take a long time, but if you wait until there is an issue to replace your radiator like most people it can happen. Doesn't seem to happen on the SC as often for some reason, or at least you don't hear about it as much. I would suggest running a separate trans cooler but not everyone wants to take the time to do that. on the stock radiator just run a hose between the 2 fittings so even if it does leak eventually it will stay in the radiator, capping off works also but might shoot off when there is an actual leak in the future.

some vehicles like the 4runners and my gx470 have the integrated cooler and a separate trans cooler inline, as in 2 coolers. alot of people just bypass the radiator one and it does fine unless you are towing etc...

 

Added to my to-do list. Although, having looked at the coolant for the first time today (I was only concerned with getting it home and whether the factory W58 setup was worth the price of admission) in getting it out on the road, I was surprised to see a lot of gunk in the radiator and reservoir, despite the latter looking pretty new and showing no signs of cooling issues. So, I may have more pressing concerns than looping the tranny cooler fittings, if there's too much sludge and/or a crack somewhere.