Finally got around to doing this Dorman 6.0L Trans Cooler install. My stock 7.3L cooler sprung a pinhole leak right at the fitting.
A bit of a pain removing everything up front. Bumper, A/C condenser, header panel. Broke the 4 outer bolts holding on the header panel. Had to drill them out and tap new threads.
6.0 trans cooler bolted right up to the stock munts, no drilling or enlarging holes.
Used 3/8" compression fitting to 1/4" FIP to connect to trans line after cutting the hose barb off the hard line. Then used a 1/4" MIP to 1/2" hose barb. This made less hose connections.
Bought 10' of 1/2" hydraulic hose and was just enough. Routed thru the stock position and then down and looped to connect to the bottom of the cooler. Had to pad a few sharp edges to keep from chaffing the hose.
I wanted to use 1/2" line all the way from hard/steel trans lines to cooler.
Or you could use just 1' of 1/2" hose off the cooler, then using barb adapter, reduce to 3/8" and use 10' of 3/8" hose to run back to the trans hard lines.
Easier routing off the bottom barbs of the cooler might have been to use 3" of 1/2" hose off cooler to 1/2" barb 1/4" MIP then 90* elbow then 3/8" barb 1/4" MIP and then 3/8" hose back to hard trans lines and slip on and clamp. If I was to do it again, this is probably how I would do it.