I would start with the connection, did you try to tighten the line?

RECENTLY some one posted concerning the seals - what exact year I do not remember...

 

I did try the upper line. It was really snug. The lower line is blocked by the lower radiator hose... which means getting to it is going to be a pain in the rear.

 

IMO you should bypass the integrated cooler, install an external, and never even bother to try and fix it. You're gonna have to end up pulling the radiator out (or at least draining all the coolant to get to the lower fitting and at that point removal is marginal effort). For 45$ you can have a much better set up without the headache.

 

That's actually what I've been thinking. Do you just cut off the old lines off the radiator and plug them somehow? Then run fresh tubing and clamps to the external cooler?

 

There are rubber lines that connect the metal lines from the rad and the metal lines from the trans right under the block. Pull the rubber lines off, cap the old metal trans lines to the rad, then run new rubber from the metal lines going to the trans to the external. there's plenty of room to run them up over the PS box and out to the front under the air intake scoop thing.

 

Been wanting to do this. Will you sketch a picture of running the hoses for us dumba$$es? I have the v8 and I can't see anything. I am still looking for the vent hose for my t-case.

 

So these are my options...since I can't decide what the leaky part is.

1.) Bypass that leaky area with aux cooler totally
2.) Replace Lines & hope it's not the radiator
3.) Replace Radiator & hope it's not the lines
4.) Replace Both
5.) Pull lines off and try some teflon tape (still require draining radiator to remove lower hose)

Basically I don't want to keep draining the radiator repeatedly... but I don't want to just replace everything for the hell of it either.

 

A aux cooler set up with total bypass will run you a total of 50$ and an hour of labor. So 120$ depending what you value your time at. Repeated diagnosis and having to drain and remove the rad to change a fitting may be cheap parts wise (~30 for coolant and fittings/lines) but will take you at least a few hours only to hope it's not the actual rad (which i doubt because its not leaking coolant).

Also an aux cooler is MUCH better for your trans in the long run. So kill 2 birds, get a better setup while fixing the issue and happens to be the cheapest option in total. I did this exact same thing when my first ZJ swap rad failed and had it warranty replaced. The warranty rad didn't like the old fittings and i wasn't about to spend 4 hours pulling the rad back out just to replace them. Amazon has Hayden fin coolers for a really good price. i paid 45 for mine but opted for a larger one that the WJ wouldn't need in normal conditions.

*ill draw a diagram/take pics when i get home

 

Topher and I have discussed this on other threads like this one. These pics are OK and you'll get the idea you need from it.
http://www.jeepforum.com/forum/f310/v8-trans-cooler-lets-seem-um-pics-ideas-3652057/

 

Thanks for sharing! I've definitely searched around a lot and seen that post and many others with various auxiliary unit setups. It's just me trying to convince myself that an aftermarket solution is actually more reliable using that factory stuff. I don't tow often, but I do run oversized tires. And I know the 42re isn't the most robust trans to begin with. I guess in a perfect world I'd run both the factory cooler and an auxiliary cooler. But I'm also cheap, so cutting lines and putting in an aftermarket option makes enough sense and would solve my leak problem without too much hassle.

I had a factory trans cooler blow out on an old Yukon. The actual cooler, not a line. It dumped all the fluid on the interstate and burnt up the trans real fast. So that may be part of my hesitation in trusting a $40 setup...

 

No worries there either. The Derale unit is strong and where it sits wont be in harm's way unless there is a collision.
The factory cooler IS the problem I was trying to avoid, so it was left out of the loop.
I just wish the WJ had a way to show trans temps via OBD.


Also, if you lose all of your fluid, in my observations from folks that post here, you'd just lose power from the trans once there is not enough pressure in the system. It won't burn anything up, it just won't go anymore.

 

The only real reason for a integrated factory cooler in the rad is to help warm the trans fluid to temp in cold weather....but the whole system is useless IMO anyway because the pump doesn't operate in park...so the whole notion of "its warming the trans too when you warm up your truck in the morning" is pointless, you still have to drive it a few miles before you get heat in the trans. The benefits of an external cooler IMO fully outweigh any benefits an integrated cooler gives you. I see no benefit to running them jointly.

1. Runs cooler (esp. in the summer)
2. Eliminates possibility of leaking water into the trans and vice versa.
3. Reduces strain on the already overworked cooling system for the 4.0.
4. Easier to work on