Help! Ford transmission experts. Leaky 4r70 trnasmission into transfer case

[hsinc]

I have a 99 Mountaineer AWD 5.0, with 69K miles. Problem is that I loose transmission fluid into transfer case. @ quarts out of transmission equals two excess quarts into transfer case. I've had input seal into the transfer case replaced. Still have problem. I was told that there may be a seal on the output side of the transmission, inside the housing that the transfer case bolts to. It would have to be on the output shaft of the transmission. Any transmission experts pout there that know if this is correct. If so is this a change at home type seal? Don't mind tackling if it is but I am not into tearing down an automatic transmission. However just a seal replacement would be OK.
Let me know if this sounds like a possible fix to my leak.

Thanks,
Harold

 

[Glacier991]

I wish I knew more about the 4r70W... but I don't, yet. Sorry.

 

[hsinc]

Any transmission people out there?
Thanks,
Harold

 

[97BlackX5.0]

i rebuilt mine and had the output shaft out of it... there are three metal clips that clamp around the output shaft and hold oil in somewhat... im still not understanding how it could leak into the transfer case though... in order for it to do that it would have to fill up the extension housing and practically pressurize it.. have you ever had the tranny replaced.... During my rebuild i was reading that on the output shaft os some transmissions... especially 2wd ones that there is a oil galley through the output shaft that has a pin in it when used for 4wd applications....in 2wd applications its used to lubricate the rear seal and bushing..... Now its possible that if your tranny was rebuilt that they used a older type output shaft with the pin and forgot to put then pin in it as it just sits in there and the walls of the tranny keep it in.... if this pin isnt there id imagine youd have something like what your describing.... but that all comes down to whether the tranny is original or not... unfortunately theres no real way to check this without disassembly... Let me know if it has been replaced before...

 

[slow-demon]

There is no seal in back of the transmission (4R70W). I have rebuilt quite a few of these tranny's. It always has fluid there. The only way the oil could get into the transfer case is through the input seal on the transfer case. Maybe the seal that was installed was the incorrect part number.

 

[hsinc]

Thanks Slow Demon,
If the only seal is at the transfer case, is it possible something else in the transfer case (worn bearing, etc) could cause a good seal to leak? Reason I am asking is, this is second seal, the original factory, plus a replacement. The original factory when removed did not look unusually worn. Could the transmission shaft have unusual wear that would allow leakage? I am going to get a transfer case rebuild kit, and redo seals and bearings. But I think something else is going on besides just a seal. Opinions?

Thanks,
Harold

 

[Blee1099]

Got any pics? We could probably help you more if we could see more definitively where its leaking from.

 

[hsinc]

The leak is internal, transmission fluid into transfer case. The way I know is that my transmission looses fluid (say 2 quarts in about 3 monthes), and the transfer case fills up. If I remove the fill plug (the top plug) on the transfer case, then I get about 2 extra quarts of transmission fluid out of it.
Nothing to take pictures of.

Harold