Using Hot Rod fuel hose AN PTFE Hose and Fittings for Transmission cooler lines

Using the correct AN Adapter Fittings

Transmission cases use different fittings then you will find in other car plumbing applications. Due to the fact that transmission cases are often constructed from aluminum it is very important to use the correct adapter fitting to prevent the aluminum transmission case from splitting. 

A common misconception with Transmission Adapter AN Fittings

If you start searching the internet for what fittings you should use to convert your transmission cooler lines to AN fittings and hose you will often be advised that NPT (National Pipe Taper) fittings will work for this application. Often times transmissions use what is called NPS or National Pipe Straight. As the name implies the threads of these fittings are cut in a different manner. An NPS fitting will seal typically using a nylon crush washer where as NPT fittings seal by apply pressure on the tapered threads of the fitting itself, this is what can cause your case to split when attempting to use NPT fittings in place of the required NPSM adapter fittings. 

How do I know what adapter fittings to use

Hot Rod fuel hose has made it easier to get the correct transmission cooler line adapter fittings by allowing you to simply select your transmission type from a drop down list. We have done the hard work researching this information for you. The transmission to AN adapter fittings can be found HERE. 

If you don't see your transmission listed please reach out and we would happy to do the research and add the correct adapter to our list. 

How much PTFE AN hose do I need to use?

When deciding how much line is required to install your transmission cooler you need to evaluate whether you will be using the built in radiator transmission cooler, an external cooler by itself, or a combination of the two. 

Most standard installations use approximately 16-18 feet of AN hose. As each installation is different be sure to measure out the required line prior to placing your order. 

What fittings do I need on my transmission cooler?

This question is more challenging to answer in an article as there are a variety of options on the market. If using an aftermarket radiator or cooler you can get the specification for the fitting from the cooler manufacturer. We then offer adapter fittings HERE.