98 Explorer 4.0 Transmission problem

[Len Smith]

98 Transmission Problem

Hi from the UK
I have a 98 4.0 SOHC and on Sunday transmission fluid was coming out of the top of the dipstick tube.
At around 1pm the truck was moved a couple of yards and parked up. At around 4pm I noticed that there was transmission fluid on the floor (quite a lot of it). Upon lifting the hood I discovered that the fluid was coming out of the top of the dipstick tube. I stated the engine and shifted through the gears, this stopped the flow but I could still see fluid in the tube. I drove the truck for a short distance and upon checking the dipstick I could see that there was still fluid in the tube (about halfway up) and that the fluid appeared to have been frothing.
The fluid level is checked regularly and no fluid has been added for
over a year (the truck does few miles) so it hasn't been over filled.
The truck was then left and the next day when I checked the dipstick it was dry, indicating that fluid needed to be added (not surprising considering the amount that had come out). I added a small amount of fluid and put the dipstick back in half way then removed it and it showed that fluid was again in the tube. The breather/vent pipe has been checked by blowing in it and it appears to be clear.
I'm guessing, but it appears to me that something is causing pressure in the transmission that is causing fluid to be forced up the dipstick tube.
Has anyone come across this problem and if so any suggestions as to what is wrong would be appreciated.
Thanks
Len Smith

 

[Len Smith]

Hi from the UK
I have a 98 4.0 SOHC and on Sunday transmission fluid was coming out of the top of the dipstick tube.
At around 1pm the truck was moved a couple of yards and parked up. At around 4pm I noticed that there was transmission fluid on the floor (quite a lot of it). Upon lifting the hood I discovered that the fluid was coming out of the top of the dipstick tube. I stated the engine and shifted through the gears, this stopped the flow but I could still see fluid in the tube. I drove the truck for a short distance and upon checking the dipstick I could see that there was still fluid in the tube (about halfway up) and that the fluid appeared to have been frothing.
The fluid level is checked regularly and no fluid has been added for
over a year (the truck does few miles) so it hasn't been over filled.
The truck was then left and the next day when I checked the dipstick it was dry, indicating that fluid needed to be added (not surprising considering the amount that had come out). I added a small amount of fluid and put the dipstick back in half way then removed it and it showed that fluid was again in the tube. The breather/vent pipe has been checked by blowing in it and it appears to be clear.
I'm guessing, but it appears to me that something is causing pressure in the transmission that is causing fluid to be forced up the dipstick tube.
Has anyone come across this problem and if so any suggestions as to what is wrong would be appreciated.
Thanks
Len Smith

 

[Glacier991]

The first suspect in these cases is indeed the vent tube.... the second is overheating.... but usually accompanied by an obstructed vent tube....

Focus on the vent tube... Remove the tube from the case....on top at the back ...and run a wire into it.... the metal tube often has slits in it to prevent siphoning water into the trans, so blowing into the end can be meaningless. If you just have a hose, that can be split with similar results.

 

[Len Smith]

Thanks for the tip.
How easy is it to remove the vent tube, and just as important, how easy is it to put it back?

Cheers
Len