if you mean the metal line going into the upper part of the radiator i can find it for 96 and 97 and since most parts are the same 96-98 i would see if those work.

 

I have a foggy recollection of reading a post that the fittings are not the same for the '98. They did put a better in-rad cooler in the '98 in order to eliminate the external cooler, so the radiator IS different than the 96-97. It would follow that the fittings could be different also, or possibly just the length or bends in the tube.

Sorry I don't have a definitive answer. The part number for the tubes for the '98 4.0 is 52079679AC. Maybe someone with a 96 or 97 parts pdf can check and see if it's the same or not.

 

These things go on national backorder all the time. It took me about three months of waiting to get the set I have now awaiting my trans rebuild. They popup on mopar inventory with no rhyme or reason. The part number is correct as kachink stated but you will also need 52079586AC which is the line with the radiator nut on it. I'll PM you a number to call to reach my parts guy who can give you recent status and put you on a list if need be if you want me to. The last set I got was $159 with shipping.

 

Looking at the 98 radiator it looks like it uses the same upper fitting as the 96-97 and 93-95. The older lower factory radiator fitting is a metal tube for the quick disconnect but all the aftermarket seem to have an adapter that threads on so they look functionally the same as a 98. You might be able to find the upper and lower radiator fittings for the 96-97 and convert. The 96-97 pipe and hose assembly is on RockAuto for $14. I converted my 93 to the 96-97 setup for about $25 total.

 

The lines arent in as bad of shape as I thought so the full lines dont need to be replaced, I was able to disconnect both lines to remove the old radiator, but the top fitting threaded out of the radiator staying stuck in the transmission line fitting. Applied penetrating lube a couple times over the course of 3 days or so then I tried locking two nuts together on the tranny cooler fitting, in order to thread it out of the line and it was a no go, brake cleaned the lube off the threads and tightened the nuts together as tight as possible by hand and still wouldnt come out the nuts just thread off the stuck in fitting, added some heat with a propane torch and that was still not effective. Unfortunately I dont have a vise to clamp the threaded fitting into to try to remove it that way either.

Here's what I'm working with:

I saw these fitting adapters on ebay when looking for a used line section and looks to get the same style fittings just not sure on the thread size and diameter, Hayden 391 says it's 5/8-18.

Anyone know if this fitting threads onto the radiator fitting so I can replace the stock line section with trans cooler line/hose and just clamp it on both ends of the hose? Since one half of the stock line section just clamps on with a spring clamp anyway, it shouldn't hurt anything as long as the top line clamp stays tight.

Id like to get my Heep back on the road asap, any help is appreciated.

 

5/8 is the thread of the fitting on the line. The fitting on the radiator looks like pipe thread but I can't tell from the pic. 5/8 is a standard SAE 45 degree male flare so you might be able to find that radiator fitting locally. Hydraulic places and better auto parts stores might have it.