Pics from the Hayden 698 transmission oil cooler install w/ before and after temps. Please feel free to ask any questions about how it's mounted and/or plumbed, and here's some general info I got from Hayden before starting this project:
- If mounting horizontally, which is okay per the directions, it doesn't matter whether the incoming fluid flow is into the top or the bottom port.
- The 698's fluid capacity is 1 quart or less, which I wanted to know b/c I'm doing a full drain and fill at the same time I install the cooler.

EDIT: After learning that cooler isn't always better when it comes to transmission fluid (explained here), I added a Derale temperature-activated valve that only allows 10% of the fluid to flow through the external cooler until the fluid temp reaches 180° F, then it opens up so all the fluid goes through the Hayden cooler. This helps ensure the fluid temperature remains optimum based on ambient temperature and other factors that influence transmission fluid temperature. Strongly suggest incorporating this valve now if you plan to add one as it will be much easier to do the valve and external cooler at the same time.

I used two of the pass-through fasteners from Hayden to attach the cooler to the a/c condenser at the top, which is tricky and involves long needle-nose pliers and patience. Standard heavy-duty zip ties anchor it to the crosspiece at the bottom. It's solid and doesn't move at all.



Plumbing - I ran the provided 11/32" hose from the lower radiator outlet to the top of the Hayden. Had to buy more - make sure it's 11/32" transmission oil hose - to reach from the bottom outlet of the Hayden to the fluid return line. (I recommend buying this in advance as I ended up having to purchase it locally and ended up getting, well, hosed.)

This view is looking up from underneath:



I sliced some used leftover hose to create protective "sleeves" where the hose passes near brackets and to cover sharp edges at the pass-through, and stuck some adhesive padding at another spot, all to protect against chafing.








Before/after at 65-70 after ~1 hour of driving with similar outside air temp:



After ~1 hour off-roading, mostly in 4HI with some 4LO mixed in: