3rd Gen Trans Cooler Lines & Possible Check Valve Delete...
 

Looks like one or both trans cooler lines on my 03 are leaking... so now looking into finding or DIY constructing some hoses similar to this...!...


Reason I'm considering this... steel trans lines are a PIA to install + new OEM's are over $100 bucks each! Before buying some aftermarket HD trans hose and tearing out the OEM trans cooler lines, has anyone attempted this or know of any aftermarket hose barb fitting adaptors that might make the trans hose connections (@ the engine mounted trans cooler) easier to install? Also, can I axe the Oil Cooler Pressure Check Valve (55056397AB) on the upper trans cooler line or do I absolutely/positively need to keep the check valve!???

I just recently did my trans lines as well. I looked at dorman, then read all the reviews. I opted for the dealer lines. The cooler to converter cooler line was like $179 and the return line from the cooler to the trans was around $100. The trans to converter cooler line was also about $100, but I did not replace it yet, as it was still good.

After doing the lines I talked with a friend that also had line issues. He removed the barbed fitting from the trans cooler via tubing cutter, got the correct fittings for the trans. He used 1/2" hydraulic lines, bypassed the converter cooler/heater and then use a fitting that has a 1/2" compression fitting to attach to the trans cooler. He said he ran the hot line up by the master cylinder to retain fluid as the check valve is now gone. He said sometimes it does not want to move right away due to fluid draining back. So just just puts it in neutral for a moment and he is good to go.

If your trans has been redone, and was updated to circulate fluid in park, then you should have no problems doing this. If the trans has not been touched, try it and just hit neutral for a moment before putting it into any gear and you should have no trouble.

This is the type of fitting he used at the trans cooler. I do not know off the top of my head what fittings are needed at the trans. Good luck!
SAE J514 Flareless - MT - Hydraulic Fittings & Hose Ends

Glad my reply was helpful. Just getting my trans rebuilt at the moment and it will circulate fluid in park now. I am in The Upper Peninsula of Michigan and my friend is in Ontario, Canada. We see some very cold temps, lol.

I done have anything against AN fittings and line. I have used them myself in racinf applications. I would try to price it out tho and compare to the cost of doing it with hydraulic hose / fittings. If you can save a few bucks and have materials that handle similar pressure, why not? Good luck.

Definitely appreciate the reply/info... truck's trans is actually stock aside from routine maintenance/a new trans solenoid. That being said, thinking of going AN8 stainless braided trans hose w/AN fittings ((-75-500F/1000 Working/5000 Burst)). Also, seems I should be able to keep/plumb in the original/OEM press check valve w/the right AN fittings(?) Actually good to know I could delete the press check valve (still might) but considering Winter temps drop to sub-zero "double" digits around here, thinking the cold might slow/delay trans fluid flow and amplify the "neutral pause" step making it more annoying/risky. If anyone sees a problem going w/the "8AN trans hose", by all means please let me know...