4R70W fluid leak.

[Mikey98Ex5.0]

Hi everyone. My 1998 Explorer has a trans fluid leak somewhere. It’s hard to tell but it looks like it could be toward the front of the trans? It looks wet around the bottom of the bell housing, my rear main seal does leak slowly though. Are there any common leak points on these transmissions?

 

[BrooklynBay]

You could try Lucas stop leak for transmissions if it's a minor leak. Do you see an occasional drip?

 

[CDW6212R]

It's likely the front seal, which at this age are rather hard and do leak. Try the various stop leaks, the Lucas one is often recommended. The rear seal is easy to change, the front, not at all.

 

[Mikey98Ex5.0]

Alright, thanks guys. I do see a drip. I did find some on the floor in my garage this past week.

 

[boominXplorer]

Check your dipstick tube oring. It will leak when parked for long periods.

 

[Mikey98Ex5.0]

Is that on the passenger side?

 

[BrooklynBay]

Yes.

 

[Mikey98Ex5.0]

Think I found my leak, looks like it’s coming from the trans cooler hoses.. Is this a common issue? Don’t mind all the nasty salt, been way to cold to wash my truck sadly.

 

[Mikey98Ex5.0]

Also, does anyone know where I could get replacements? Or am I better off going to a hardware store and getting hose? Anyone know what size the hoses are? Looks like maybe 1/4” or something close.

 

[Turdle]

Any auto parts store like NAPA will have the transmission hose. Make sure you ask for 3/8" rubber hose for transmission-hydraulic use. Tighten the clamps just tight enough to prevent the hose from rotating on the fitting when twisted with your fingertips. .

 

[CDW6212R]

That is a common leak location, the hoses shrink over a long time. They can be just tightened up in most cases, and be fine for a long time still.

 

[Mikey98Ex5.0]

I’ll replace those hoses, might as well. Id imagine they’re original to the truck. Thanks for the help guys.

 

[BrooklynBay]

Since you have to replace the hoses, it's a good time to add an external inline filter for the transmission fluid.

 

[SupaSwope]

Mine leaked like that randomly, i tighten them up and never had a leak since.

 

[CDW6212R]

Mine leaked like that randomly, i tighten them up and never had a leak since.

I've done that with each of my five Explorers over the years. Age makes the hoses shrink/leak. I have great replacement hose material, but rarely need it. I used some when I added an external filter to my 99 mail truck, which added a quart of capacity. I'm ready to do that even more now, two external filters for the ATF and oil, the special bypass filters catching material down to 2-3 microns. More fluid is better, and I like it showing transparent on the dipstick.

It's located right in front of the radiator support, the body mount bolt pocket.

 

[Mikey98Ex5.0]

Any auto parts store like NAPA will have the transmission hose. Make sure you ask for 3/8" rubber hose for transmission-hydraulic use. Tighten the clamps just tight enough to prevent the hose from rotating on the fitting when twisted with your fingertips. .

3/8 OD or ID? Rockauto lists 5/16 ID.

 

[Mikey98Ex5.0]

I ended up getting 3/8” ID hose.

 

[CDW6212R]

They are 3/8", Ford upgraded around 1990 from 5/16", the bigger size helps flow and cooling better.