top loader vent

[MOTORHEAD]

How critical is the venting on the top loader tranny ?.
Mine seems to blow oil past the rear seal if I wind it up, slight drip under normal driving.
seal has been replaced twice in the past year.

[ERA174]

Could be the bushing in the tail shaft housing or the slip yoke are worn which will accelerate the wear of the tail shaft housing seal. First check the level of the lube, over filling will cause leaks. Also, make sure you have a vent, OEM is just a small hole approx. 1/8” in the top cover of the main gearbox housing. Some tail shaft housings were also upgraded with a vent on the top of the tail shaft housing a couple of inches back from where the housing attached to the main gear box. If the lube level is correct and you have a vent, the problem is likely the bushing and or yoke and a new seal. The bushing, seal and yoke can all be easily replaced. Make sure the lube is leaking at the seal to yoke and not the seal to tail shaft. If leak is at the tail shaft where the seal is driven into the housing, a new seal and a lite application of the “right stuff” on the o.d. of the seal prior to driving it into the housing should suffice, if the bushing and yoke are in good shape. One other remote possibility could be a bent output shaft, don’t go down that rabbit hole until you have ruled out all the easy fixes first.

[MOTORHEAD]

ERA174: thanks for your input; I can feel a very slight movement in the yoke to output shaft/sleeve fit, maybe .001,002. yoke tube has no sign of wear.
Lube level is slightly below fill hole..
My problem might be that I can' fit a proper seal ( Ford C-4 or C-6 depending on output shaft size )My tranny is "big-in, Big out " so a C-6 seal fits the yoke tube, but is too big for the counter bore in the aft recess of the tail housing, so I've been using a generic seal from the local bearing dist. That's what was in it when I bought the car. t

[MOTORHEAD]

con't; The housing should have been bored to the seal O.D. but wasn't. I'm trying to fix this without pulling the trans, as that requires disconnecting the engine so the engine can be tilted up at the back to allow the tranny to clear the non-removable crossmember to get the trans out from the top. I'm trying to see if one of the T.L. specialists might have a proper seal.