Changing rear gear oil...

[Daryl]

Haven’t seen the backside of the rear diff enough to notice or remember off hand the drain and fill points of the rear diff cover on my stock ‘95 Cobra SVT 5.0, but was wondering if there are the traditional upper (fill) and lower (drain)bolts that make it easy?

Reason I ask: I was just under my ‘12 Ram chasing an EVAPORATE issue and didn’t see the traditional upper and lower bolts for the upcoming 144k rear gear oil change. So, while my car is still in the shop, thought I’d ask after the Cobra’s set up.

Thanks!

 

[BigBore96]

I dont recall if/where the drain plug is but the fill plug is on the drivers side just behind the driveshaft bolts.

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[trebor3170]

No drain plug, unless you have an aftermarket cover, you just loosen the cover and let it drain. Make sure you can get the fill plug loose first, if you drain it, then can't remove the fill plug, you're now looking for an aftermarket cover with drain and fill plugs!

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[Daryl]

BigBore and Trevor,
Cool, thanks! I appreciate both replies. Should make the oil change go better

 

[Daryl]

What weight rear gear oil? 8.8” rear. ‘95 Cobra 5.0, 5-speed manual

 

[Randall Garner]

You can use 85-140. Need to add the friction modifier additive. Can get the same place you get gear oil. If I recall it’s GL-5 rated. And it needs to be listed as a limited slip or positraction approved Oil

 

[Daryl]

You can use 85-140. Need to add the friction modifier additive. Can get the same place you get gear oil. If I recall it’s GL-5 rated. And it needs to be listed as a limited slip or positraction approved Oil

Not 75w/90? Glad I asked! Thank you, Mr. Garner.

 

[Randall Garner]

The clutches need to greater range as with the additive

 

[dwcopple]

I used full syn 75w90 gl5 and the Lubeguard LS additive this summer. Working great and quiet too!

 

[Wmac]

x2 on 75/90 synthetic with bottle of Ford friction modifier.

 

[Daryl]

Is there a particular rating on the modifier I should look for?

And...
While the cover is off, how can I determine what gears are in there? Are they stamped somewhere? Or count splines? Or ??? It’s probably bone stock, which I believe are 3.08’s, but if I can confirm while I’m in there, I’d like to know

 

[apsmith49921]

You can calculate gears with everything on. Spin the wheel one time and count the drive shaft rotations.

Counting teeth also works

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[Daryl]

Ok, thx! Is there a conversion table online somewhere that’ll tell me “x amount of teeth = x amount gear ratio”?

 

[DKblue98GT]

If the rear is stock there should be a tag on one of the diff cover bolts that tells what ratio it has.

 

[Daryl]

Thx, DKblue. I recall seeing a metal tag affixed to one of the bolts. I’m going to go crawl under, clean it off(!), and hope it’s still readable. Stand by...

 

[Daryl]

If I’m reading this right, it’s a Limited slip (the L on the tag) with 3.08 gears (the 08 following the L)

 

[Daryl]

So it looks like this is how it reads:
Top: S 207C (?) or is that a partial zero?

Bottom: 1 (maybe?) L 08 88 5B14

 

[evilcw311]

Yeah that’s a 3:08.


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[Daryl]

Confirmed! Thank you, evil!