BroncoII4x4.com

I have a 87' Bronco ii with the ever so horrible A4LD transmission. I seem to blow front seals in the last 2 replacements I put in it. I have read articles on how bad the transmissions are but are they really that horrible. I mean from my experiances yes. But does anyone know what could be causing this? The lastest transmission i bought with about 25000 miles on it. The problem only occurs during highway driving of 30 miles or more.

check the vent

All the vents are clear. Im beginning to think its something in the valvebody or maybe a pump issue causing to much pressure?.?. It just seems really odd that I would get 2 of them in a row with the same issue.

I don't know how deep your into iron, so the following is a little I've learned over the years, about seals an turning iron.
Most transmission front seal issues are from, a transmission bell housing that is not dialed to the engine, or there is a problem with the iron the seal is trying to seal.
The seal drain could be plugged.
A bent or mis- aline'd flywheel can also cause a seal issue, as well as a converter that is not running true do to out of alinement or damaged flex plate holes.
Stacking of + or - of spec's will also cause problems that will not be found without the help of a dial indicator, the tech spec's, an time.
I've also found the wrong seals installed, or correct seals installed improperly.
Then again I've seen seals being blamed for a leak somewhere else.

I would suggest taking it to someone that has the ability an tools to correct the issue for you, and be done with the heart break, then enjoy the truck.

also get the updated flywheel spacer