We're all seen Mark's 4R100 tranny service how to.

2004 F250 5.4L Transmission Flush

The one above from JM has a few more pics. This thread serves as a reminder to get yours serviced. It's not a difficult job. While down there, go ahead and get 2 more qts for the transfer case. Mine (tc) was pretty dark after 60K miles.

Anyone know what this orange sticker in reference to? http://www.thedieselstop.com/faq/949...les/992111.pdf

 

Pic 2- here's the unbuttoned cover.

 

Pic 3. The requisite magnet and bucket photos.

 

Pic 4, of the Tcase service - need a 10mm Allen wrench or socket-type.

 

Adding Mercon V back in (used another container for ease of re-filling).

 

I thought the T case used T case fluid, not Merc-V. That is what I bought at least.

this stuff

 

^^^^^^

Yes, but I did not use it(XL-12) either. Since the transmission and transfer case have no seal between them I use the same fluid in each.

I used amsoil in both.

 

While down there I noticed the rear drive shaft boot was split. Will order a replacement.

 

When I had my t- case and transfer out a while back, I did not see where fluid could exchange between the two.

 

What happened to the seal between them that was there from the factory? Why did you remove it? How do you control the fluid level in each without this seal?

 

There is NO seal that i am aware of on a 4X4. All there is is a "dam" for lack of a better word. There is a gasket between the transmission and extension shaft housing, but that just prevents transmission fluid from leaking onto ground.

The dam allows transmission fluid to pool in extension housing. However the two "can" exchange fluid when that pool overflows the dam.

If you don't believe me try to buy a seal....all you will find are seals for 2wd models. I know I bought 2 seals from NAPA, assuming one had to fit because NAPA could not figure out which one I needed. After all was apart....no seal. Not even a place to put a seal.

See for photo:
http://click-a-part.com/products/4r1...ant=9996994052

Note the weep hole at bottom of "dam" in extension housing.

Mark, you are the expert when it comes to transmissions, and I defer to your expertise from numerous posts, so if I am somehow wrong please educate me...thanks

 

There's a seal on the input of the transfer case that keeps the two fluids separate.

 

That does make perfect sense. It must be inside transfer case...that's why I could not see it.

And asking for a rear transmission seal was pointless, it probably called a transfer case input seal.

Thanks Mark...

 

Is this seal replaceable without taking t-case apart?