Just got my built 700R4 the other day and was trying to find out what I'm going to do with the cooler. I found out that the threads in the transmission for the cooler lines are 1/4 NPT. After doing some research I found out that the sizs of - X AN equals that number in 1/16ths of an inch. Therefore a -4 AN would be 4/16 or 1/4. Now seeing as how the adapter will be a 1/4 NPT, should I match the inner diameter and go with -4 AN? Personally I was thinking about going with -6 AN in hopes to get more volume/flow to the cooler, I just don't want to have any issues or restrictions. I Plan on using a cooler that has provisions for using adapters for the stainless steel braided hose. Anyone have any thoughts??

 

the AN hose fittings choke down a lot on the nipple part. Use -6.

I always figure 1 size larger than what its supposed to be.

1/4"-6an, 3/8"-8an, 1/2"10an ect. That just me though.

 

1/4" NPT is something like 3/8" OD. ID can vary depending on the fitting. It's recommended to use 3/8" (-6) line for the tranny cooler lines.

No matter what you do, there's still going to be a smaller restriction in the cooler port inside the transmission.

 

AN fittings are all measured in 1/16th's of an inch.... -4AN is 4/16" (1/4"), -6AN is 6/16" (3/8"), -8AN is 8/16" (1/2").

 

Well, thanks guys, you pretty much confirmed what I was looking to do. Seems that using the 1/4 NPT with an adapter fitting for 1/4 to -6 AN is the way to go. Then I ll run stainless steel braided hose up to the cooler and be done with it. Thanks alot for your input!!