My factory power steering cooler rusted through a few months ago, at the moment I just have a loop of rubber hose in there but I want to put another cooler on there.

Can a power steering cooler be TOO big, or is it kinda like a transmission cooler...the bigger, the better?

I ask because I figure a transmission cooler will work great for that, but many of them are around 10x6" and I didn't know if that was too big.

I'm not really that concerned about the fluid really getting super hot, but since I do have a heavy truck which will soon have 33's on it, I thought maybe it'd be a good idea to have something there.

 

You should be fine with the tranny cooler.

Many of the older trucks have so much oil and dirt built up on the cooler lines, they can't be working.

I guess another option would be replace the stock cooler.
A five foot piece of 3/8" steel tubing and a tubing bender should have you back in business.

 

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A word of advice, it's not the parts house's fault. In '94 there were IDI non-turboes, IDI turbos, and the first electronically computerized Powerstrokes. If you have a '94 IDI, when ordering ordinary parts you'd be wise to order for a '92 or '93 then the parts house knows what engine, etc, you have.