So I see some built up road grime in two places - see pics. Based on some research on these forums, the first thing I want to try for pic #1 is a pinion seal replacement. I'm trying to see if pictures 2 and 3 are related or not, but it seems to be coming from the gasket in between the transmission and the transmission extender. If anyone has had experience with these problems, I'd appreciate the input!

Picture 1: will probably try pinion seal replacement.

Picture 2: I see built up grime on the transmission extender - could it be coming from a bad seal on the yoke?

Picture 3: grime that seems to be coming from in between transmission case and the transmission extender. Will look into replacing a seal between the two faces.

 

Make sure you take a rotational resistance reading of the pinion flange before you begin replacing the seal. The preload for the pinion bearings is set and maintained by a crush sleeve on the pinion shaft between the pinion bearings.

The shop manual procedure to replace the pinion seal requires a new pinion nut and crush washer be used.
WIth an inch pound beam or dial style torque wrench you rotate the pinion by the pinion nut and record the resistance in inch pounds. This is the number you want to shoot for on reassembly with the new crush sleeve.

There's a few good threads on here and on the web in general on the ford 8.8 axle pinion seal replacement. Do some research and decide if it's something you feel comfortable doing, then go from there.

 

Thanks HawaiiMud, I saw all the DIY/how to posts on that subject. Still on the fence on whether I want to do myself or not. But before doing that I'm trying to figure out both sources of the leaks - do you have any idea/opinion on the other pics?

 

I'm not as familiar with the auto trans, but I do know there is a case vent that can get clogged and cause high pressure and seal leaks in the auto trans. My first step would be to clean everything off really well and drive it, try to see if you can pinpoint the leak. The output shaft seal looks like it's leaking in pic 2, but pic 3 could be from higher up on the trans and it's just running down to the extension housing seam.

 

Appreciate the response. I'll look for the case vent and see if it's clogged. I've already cleaned all leaks up for that exact purpose - to see where it's coming from and how fast.

Agreed with your comments on the output shaft seal - though there's a bracket that separates the two pictures (transmission case/extension interface and the output shaft/driveshaft area), so it doesn't seem likely that the leak could run from one side, over a bracket, and travel "upstream". Because of this, I'm suspecting two separate leaks. Hopefully that made sense.