Hey guys, 20002, F-150 SCrew, 5.4 4R70w, tranny is only leaking when I drive the truck for the day, not on small trips, so I believe it has to do something with the temp of the fluid. I know there is an overflow on top made specifically for when the tranny is overfilled, but it has leaked when I can't even get a reading on the dipstick. All the pan bolts are tight, so I really think it is coming from the overflow, but why would it happen when I'm not overfilled in the tranny?

I have Merc V in it.

Thanks guys.

 

You sure you don't have a leaky seal? Have you been underneath to try to find exactly where it might be coming from?

 

Yeah been underneath it and made sure that all of the pan bolts were tight. I can also see fluid running down the side, I will double check though.

 

o-ring on the dipstick tube?

 

It looks like its coming down the drivers side of the tranny, is that still a possibility?

 

If it is coming out the overflow because of overheating, then it is a good possibility the trans is slipping badly causing the the overheating. Probably in overdrive.

 

Should I try and run without overdrive and see what happens? And I assume its slipping badly becuase its time to get rebuild?

 

It wouldn't hurt to try it. If it doesn't leak, then you have your answer.

 

I'll give it a try today since I have some driving to do. I can't really notice it slipping, from a stop, or in shifts, but i'll try and be more observant.

thanks guys.

 

I think the best way to find it is going to be to get the thing as clean as possible first and then drive it in a way that you know it will leak. Then you start looking/feeling around working your way from top to bottom to see where the highest wet spot is and that will make it easier to pinpoint.

The vent is right where the extension housing bolts onto the transmission case and on the very top. If you have a 4x4 then there is a hose attached to it that vents at a higher point to keep water and mud out.

Darrin