evilstevie

This looks like a PITA to replace - not so much from the cooler in front of the radiator, but when I follow the lines back to the tranny they go up past the pan and out of sight. Not sure how to even access them on the tranny end. The leak is right after the connection at the cooler, so kind of a tough spot to cut and repalce, I think. Thought about buying a complete new line, and then just splicing it together with some high pressure tubing back by the transmission. I doubt this is even a high pressure application but I want the repair to last obviously.
Couple of pics attached - here's the leak by the cooler:


And the other end where the line vanishes up into the side of the tranny:


what's the smartest way to fix this? thanks

Tundra Dweller

The lines at the tranny are not that bad to get at. Pre-spray all the fittings, wait a day or so and use a good 5/8" & 3/4" open end wrench on them. I just had to push the cat. exhaust shield to get at them when I used the top one for a trans fluid change. I think there is one bolted bracket to the block for support you will need to remove. They are not buried or routed badly at all. Just be careful not to kink the new lines when replacing them.
I would not try to splice hose or other sections of line into it.

01-7700

2001 F150 5.4L 7700 series. I was plowing and noticed a trail of blood. Rotted tranny cooling line is leaking so much I doubt I could get the truck anywhere for service without running the tranny dry. I'm thinking I could make a short bypass line to come out and back in the tranny for the winter. Or just remove the lines from the nuts and weld caps on them to plug the holes. Questions - what do the line ends look like? Are they flared like brake lines? Is there a pump that pushes fluid through the lines or does it work on tranny pressure? Would capping the nuts harm anything? I'm thinking option 2 would be easier for a temporary solution. Thanks.

DaytonLax14

Mine were just like that. Had them replaced by a local shop for $207. Took them a morning to do it.

01-7700

Thanks - I'm going to remove the lines from the transmission tomorrow and cap the nuts, replace the lines when the weather gets warmer.

patbob

If you do a hose splice, use tranny cooler hose -- its designed to stand up to both the tranny oil and the temperatures. Being as its winter, you'd probably be able to drive to a shop before the tranny overheated.


Not sure if you want to do plowing till its fixed as I'd think the load of pushing snow around might put a lot of extra heat into the fluid. Also, I'd be more inclined to do a bypass than cap the lines. One will have pressure on it, and capping it will generate more backpressure on that pump that it's used to.


Had the same thing happen to another car a number of years ago. hardline wasn't rotted but rubbed through. I just did a hose splice and it held up several years until the tranny finally wore out and needed a rebuild. Had the shop replace the hard lines while there were in there since they had to come off anyway.

01-7700

I'm finally getting around to replacing the tranny cooling lines on my truck. Can anyone verify the flow direction for me? It looks to me like the fluid comes out the rear flange, flows through the aux radiator, then to the main radiator, then back to the front flange on the tranny. Not that it really matters - I'm just trying to understand how it works. What are your thoughts on eliminating the aux radiator? I don't tow with this truck, just plowing in the winter and occasional light duty hauling. Thanks.

PerryB

I think you have a 4R100 transmission. If so its the other way around.
Front flows forward/rear return.