I'm getting ready to install a B&M plate trans cooler on my Mark VIII and was wondering if those of you that have already done it, if you eliminated the OE cooler, or ran it in conjunction with your aftermarket cooler? The cooler I've got is rated at 24k GVW but to tell you the truth I don't really know how that translates into a coolers cooling ability.

I ran mine with the OE cooler as did 3 of my friends

My recommendation would be to plumb your new unit after the radiator and before the tranny. This will give the fluid the maximum cooling enviroment (length of time) capability. In SC where you live you still have some cold weather so bypassing your radiator totally would not be a good idea. This should also add life to your fluid and tranny so you are doing a big thing to help your tranny last. I have it done to all of my Marks as well.

IIRC, the TOP line is the return to the trans. thats where i will be tapping in when i install mine this weekend. someone PLEASE correct me if i am wrong, so me or this guy doesnt try to cool the fluid before it hits the rad

Roadboss has it right, At least that's what I did & it works great! Yes, top line is the return on a mark VIII.