Hi all,

My rear diff is leaking, I think the cover seal is bad. How hard are they to replace myself? I called up a mechanic in the area and they said they are a b*R$# to get at and it would take like 5 hours of of labor. Really? Is it really is that hard to get at? If it's going to cost me that much I'd rather let it leak and just make sure to check the fluid level monthly.

02 GT manual.


Thanks.

 

Pretty simple to change the gasket, gear oil is messy though. Have to find the fill plug too. Cant remember off hand where it is on the 8.8..

 

undo the bottom 4 or 5 bolts, allowing the fluid to drain out the bottom into a pan

remove the rest of the bolts, and remove the cover, may have to use a flat screw driver to pry off

use a razor knife or gasket scraper to remove old gasket

place new gasket in place place cover back on and put bolts back in, u should torque the bolts to get the right tightening force, but if u just tighten very snug u SHOULD be ok

replace w/e the recoomended gear oil is for a ford 8.8 and fill it to w/e the spec is

sorry i don't have that spec with me but im pretty sure its something like fill to a little below the fill plug

hopefully that helps

 

Thanks, I was hoping I could do it myself as long as there was enough room to get at the bolts. Wonder why the hell they said it would take so long/cost so much....

 

I like using hi-temp silicone, but the gasket os OK....Do it yourself! Don't forget the friction modifer when re-filling...

 

I think your garage just wanted to rip you for some easy cash. When I changed the oil in the rear diff. I used the liquid gasket though, real easy to do if you can turn a wrench.
Also, make sure you have a nice size basin to catch the oil, a little messy.

 

I'm not entirely sure if it applies to stangs, but in F Series and other Diffs you MUST HAVE Friction Modifier. Look into this. Call up your local ford dealer and ask.
It's most likely just regular 80-90 Gear lube, but you may need FM.

 

I'd clean the bottem of that rear really well and watch for the leak. The cover seal is usually not the culprit. It's usually the pinion seal at the front of the diff. BTW, Lubelocker seals cover seals FTW if that's what it needs. From the factory they came with RTV.

 

You're half right.. Often the pinion seal is the culprit, and driving would force the fluid to travel to the back of the diff, causing the owner to assume it's a leaking diff without thorough inspection beyond a cursory glance.
However, many of the older Diffs featured Vent tubes to allow pressure release from the Diff. When this vent corrodes, pressure release is negated therefore building an air pocket and literally breaking the bead of RTV Silicone around the Diff cover.
This, however doesn't usually apply to Stangs as, to the best of my knowledge most/all of them (At least, newer models) do not feature this vent. Hence, why I feel you're half right

It is, however not at all uncommon for Silicon to simply fail. Especially if not properly applied in the first place (Not implying anything).

 

you only need friction modifier if you have a LSD, or some version of that, if its an open diff then you don't need that