Rear End Leaking - Pinion Seal?? (Pictures Inside)

[vipergts281]

Noticed 2 very dark (jet black) drops on my floor. Looked under the car and at first thought it was coming from the diff cover. But it looks like it is coming from the pinion seal and running down and dripping at the bottom of the diff.

In the second pic you can see oil above the area...guessing it's just from the air while driving blowing it up there??

Would you say this is a pinion seal leak? If so, what is all needed to repair? I'm 99.9% sure I will be paying someone to do this.

Is this $29 pinion flange from AM what needs replacing? Anything else I need? I'm thinking I may have my diff fluid changed while I'm at it.

My rear end makes a noise, sounds like tire noise but much louder. Instantly goes away when I am in neutral. Could this sound be because of the pinion leak? Or gears?

I tried adding fluid to the diff today but cheese and FN crackers what a pain in the ass...I wasn't able to turn the fill nut to remove it. Had trouble getting something in there and when I did, I had no room to turn it.

 

[WHITESTRIPES]

Ya that looks like a pinion seal, pull your drive shaft out to really find out. It can be easy to do if you reuse the old crush sleeve and count and mark the turns of the pinion nut. ( if it is the same design as a fox, I haven't done one on a cobra yet)

 

[big dad]

Mark the location of the driveshaft yoke and pinion flange with a crayon or bright Magic Marker so you put it back together in the proper index.
Next remove the driveshaft and take a chisel and hammer and put a mark on the pinion nut and end of the pinion so the marks line up. Also mark the pinion flange to line up with the other marks before removing anything.
Remove the old seal. Put a pan underneath to catch the diff fluid when you remove the old seal.
Pack the new seal on the backside with grease or vaseline. This is done to prevent the spring on the backside from popping out when you hammer the new seal in.
Use a Scotchbrite pad to polish the companion flange surface that the seal will be riding on, just get it cleaned up and shiny. Put a little grease on that area also. Then pound in the seal till it stops.
When those marks are all lined up reinstall the pinion nut (with a silicone bead on the backside), and tighten down the nut utill the marks line up.
Refill the diff with fluid and friction modifier until it comes out the fill hole, reinstall the driveshaft, clean off the diff from the old seal leak. Road test and recheck for leaks.
Based on info you may have a bearing(s) problem if the noise does not go away. Good luck.

 

[vipergts281]

Based on info you may have a bearing(s) problem if the noise does not go away. Good luck.

Thanks, I've been researching and it seems like it's not that bad a job...as long as you mark everything properly.

How bad is it to replace the bearings? I assume those are in the differential?

And can I just fill the diff when the flange/seal is off or do I need to use the fill hole in the diff? I only ask because I tried getting the fill hole open earlier today and it was a giant pita. Without removing my exhaust pipe, I don't see how one is able to turn the wrench??

I just ordered this from AM. Is this all I need? Besides fluid, friction modifier, loctite?



http://www.americanmuscle.com/frpp-pinion-flange-0304cobra.html

 

[big dad]

You have to install the diff fluid after you put the pinion flange back on otherwise it will leak out and not be at the correct level.
As far as the diff plug being difficult to remove my suggestion would be to spray it down with some PB Blaster and let it sit overnight. You will need a 3" 3/8 extention and a long handle 3/8 rachet wrench, also try heating up the plug with a propane torch then hit it with cold water. Do this before you take everything apart.

 

[vipergts281]

You have to install the diff fluid after you put the pinion flange back on otherwise it will leak out and not be at the correct level.
As far as the diff plug being difficult to remove my suggestion would be to spray it down with some PB Blaster and let it sit overnight. You will need a 3" 3/8 extention and a long handle 3/8 rachet wrench, also try heating up the plug with a propane torch then hit it with cold water. Do this before you take everything apart.

Awesome, thanks for the tips. :beer:

Any comment on the thing I ordered from AM? Isn't it missing the actual seal? Seams to be just the flange. Don't I also need something like this? http://www.autozone.com/drivetrain/pinion-seal-rear/duralast-pinion-seal-rear/12009_160620_0/

Seems like I just need a new seal and I would reuse my current flange, no?

 

[006]

http://www.svtperformance.com/forums/showthread.php?922686-rearend-is-leakin-again

and

http://www.svtperformance.com/forum...-driveshaft-vibration-and-driveshaft-indexing

With the flange you purchased, match the markings on the flange with the yellow dot on the driveshaft. Line them up as close as you can, bolt them up and you're set.

 

[big dad]

Awesome, thanks for the tips. :beer:

Any comment on the thing I ordered from AM? Isn't it missing the actual seal? Seams to be just the flange. Don't I also need something like this? http://www.autozone.com/drivetrain/pinion-seal-rear/duralast-pinion-seal-rear/12009_160620_0/

Seems like I just need a new seal and I would reuse my current flange, no?

With as many miles on your car as indicated I would install the new companion flange, and yes that looks like the seal. Make sure to pack the spring side of the seal with grease as previously mentioned.

Additionally it would be best to install the seal with a seal driver to prevent damage to the new seal, plus it makes the job alot easier.

 

[vipergts281]

With the flange you purchased, match the markings on the flange with the yellow dot on the driveshaft. Line them up as close as you can, bolt them up and you're set.

Great, thanks!

With as many miles on your car as indicated I would install the new companion flange, and yes that looks like the seal. Make sure to pack the spring side of the seal with grease as previously mentioned.

Additionally it would be best to install the seal with a seal driver to prevent damage to the new seal, plus it makes the job alot easier.

Yeah, I'm going to install the new one for good measure.

Any tips to getting the fill hole nut loose on the diff cover besides what you mentioned (3" bar and long handle)? I feel like it should have been easier than it was, like I'm missing something.

There just seemed to be no room to do anything there. Maybe I'll just pop one of the exhaust pipes off as a worst case scenario.


I may just end up getting new gears thus having a shop do all of this...I wouldn't even begin to think about attempting a gear install.

Any idea on a ballpark price for a gear install? Going to call some places tomorrow but just curious to what I should be expecting.

 

[NastyNate420]

In the trunk there is a rubber grommet that you can pop out and fill the rear through there.

 

[vipergts281]

In the trunk there is a rubber grommet that you can pop out and fill the rear through there.

Never heard about this grommet. So you're saying I can just run a tube through the grommet into the fill hole?? Filling it isn't the problem I'm having, getting the damn fill plug off is.

 

[NastyNate420]

Well there the trick to filling it cuz its a PAIN!
As far a getting the plug out I just used a 3/8 drive extention and a breaker bar
If its giving you problems then spray it with some pb blaster and let it sit for a day or 2.
Lemme know if you replace that seal. I have a leak too but didnt want to mess with it until I rebuild the rear end.

oh yeah and Ive heard from 300 -500 for a gear install

 

[vipergts281]

You and big dad make it sound easy...3/8 socket and long bar, haha. I just don't see how in the hell I'm going to have the room to move the ratchet back and forth.

But at this point I'll just have it done when the gears go in.

And yeah, my research seems to put it in the $300-500 range as well.

Thanks!

 

[Tractionless1]

You and big dad make it sound easy...3/8 socket and long bar, haha. I just don't see how in the hell I'm going to have the room to move the ratchet back and forth.

But at this point I'll just have it done when the gears go in.

And yeah, my research seems to put it in the $300-500 range as well.

Thanks!

I had a entire Mark VIII rear end tore down, the housing checked for cracking etc., cleaned, machined for Mark Williams billet bearing caps, gears installed, Detroit True Trac added, solid crush sleeve installed, and all new bearings installed, everything but the cover in the same price range. He'll set up your gears for you're car's usage, street, drag, road race, mixed usage etc. PM me if you're interested and I'll put you in contact with the gentleman.

For good measure