Would you replace factory trans cooler with auxiliary?

[joney]

I have a leak in the metal trans lines going to/from the trans cooler that's in the radiator. As it's a stock 98 XLT with 174K, and no service records of anything but the radiator being replaced, would it be a good idea to just put an auxiliary trans cooler on in front of the radiator and so eliminate possibility of the internal cooler dumping coolant in the tranny? (and plug the lines in/out of the radiator) Also, just curious, how does one flare the metal lines that stay on the vehicle, so as to attach transmission hose to them, without wrecking them? As I haven't done this, not sure if it's smart to try to DIY it. One local shop already said patching the existing lines with hose would be expensive.. Your experience/advice would be appreciated. You all have helped me a lot already! Note, I don't plan on towing or driving in the (nonexistent) mountains here, ha ha!

 

[C420sailor]

So your truck does not have a factory aux cooler? It only goes through the rad?

Add one.

The factory one is okay. I want to upgrade my factory one.

Running through the radiator alone is insufficient, IMO. Heat is a big enemy of these transmissions.

As for whether you want to bypass the rad after adding the cooler, that’s your call. Depends on your climate, IMO.

 

[Mbrooks420]

Agree with above.

Id keep the existing piece of line that flares into the radiator. I’d go to the aux cooler with rubber lines. The rubber lines also give an excellent way to do a fluid flush.

 

[joney]

So your truck does not have a factory aux cooler? It only goes through the rad?

Add one.

The factory one is okay. I want to upgrade my factory one.

Running through the radiator alone is insufficient, IMO. Heat is a big enemy of these transmissions.

As for whether you want to bypass the rad after adding the cooler, that’s your call. Depends on your climate, IMO.

Thanks for the quick answer! I don't actually know if there is a factory aux cooler also! Vehicle is stock, did the 4 door 4x4 98 XLT generally come with one? For climate, it's hot here in July, (80s up to 90s) and a lot more cool/arctic weather in the winter. Mostly short trips in the Ex. IF it turns out I have already a factory aux cooler, is it wise to plug off the radiator one, and just go with the auxiliary? Or add another auxiliary? Really want to avoid the coolant in the trans issue, as the quality of the one in the radiator is unknown to me. Want to avoid trans trouble on the high mileage original.

 

[joney]

Agree with above.

Id keep the existing piece of line that flares into the radiator. I’d go to the aux cooler with rubber lines. The rubber lines also give an excellent way to do a fluid flush.

Part of the steel? line is leaking. Is it doable to saw off the leaky part, and can one flare what's left on the car, before adding the hose to the aux? Do you DIY this or have a shop do it? Sounds like you're leaning toward keeping the cooler in the rad also, although I seriously wonder if a particular size aux would do the whole job alone.

 

[Pete Deering]

I replaced the cooler lines from the radiator too the tranny. The line nears the tranny rusted out cause a leak. I just replaced the steel lines.I also remove the wheel liner to access the tranny lines. Used compression fitting ( union) to joint the two lines. Making the flare fitting, you need a flaring tool. You will need these oil because your brake line will rust out. I replaced almost all my lines. I live I the rust belt.