I hate that my B+M cooler has 1/2 NPT inlet/outlet threads and I have tiny stock transmission cooler lines running to it. I originally spliced off where the metal lines turn to rubber up by the radiator, and ran rubber cooler line to the cooler with 1/2 NPT barb fitting adapters. Im looking to bring the lines up to par and have put together a nice part list to help anyone else who wants to ditch their factory lines. You must change the adapters to the cooler to match your specific cooler application.

1. Cooler: B+M 70274

2. You replace the threaded cooler fittings on the transmission with an adapter -8 AN (male, line side) to 1/4 NPS (male, transmission side) fitting. These are the ones I found on Ebay:

8 An x 1 4 NPS Trans Cooler Fittings GM T350 400 700R 4L60E | eBay

Sellers name is sweet_performance in case the link goes down.

3. From there you convert over to run braided AN style hose. So you need a female -8 AN (transmission side) to a hose end and it needs to be a 45 degree angle to exit the tranny: Summit part number SUM-220886. Thats for the red/blue but there are other colors available. You need 2.

4. Stainless braided cooler hose -8 AN. 20 ft. to be safe, cut to length: Summit part number SUM-230820

5. You need ends for the cooler. This will vary between coolers but 1/2 NPT female is pretty popular on plate coolers of decent size. So for that you would need an -8 AN hose end (hose side) adapted to 1/2 NPT (cooler side) male threads: Summit part number SUM-240103B. An alternate part number for a different brand: FRA-190168

6. If you want to change the way the line goes into your cooler here is a 45 adapter: Summit part number SUM-240110

7. -8 AN aluminum wrench (The fittings are easy to mess up): Summit part number SUM-900108

This replaces both stock cooler lines from the tranny all the way to the cooler and back. :usa:

Installed and running (pics soon): The trans has an HD2 kit, firmed shifts through HPTuners, and a 4k Yank. Thinking the bigger lines may kill some pressure for shifts. First impressions are great (cant go WOT until clutch packs break in), I can feel a low speed part throttle 1st gear >2nd shift. It doesn't quite feel right so I may work on that in the tune. Mid throttle/speed shifts feel perfect. No complaints. Fitment was great also with the 45s. I will get a pic of that.