Rear diff cover

[vegas39]

my rear axle has a slight drip from the cover and I figure it's time to change the oil in it anyway.
Does anyone know if their is a gasket on that, or is it just rtv?
Also, how much oil does the axle hold? Gonna pick up what I need today and change it tomorrow. Thanks!

 

[Ddizzy77]

Think three quarts, I always go until it weeps out of the fill hole

 

[catbird7]

Just use RTV gasket maker. No gasket required.

 

[franklin2]

Before I went to the trouble, I would put that drip on my finger and smell it. If it smells like gear oil, ok. But it may be engine oil or anything from up front. You would not be the first to think their rearend is leaking only to find that it's a oil leak from something up front and it's blowing back and hitting the diff housing.

 

[Thewespaul]

There are gaskets available for them, I like using them instead of rtv.

 

[Macrobb]

I use "one minute gasket" by Permatex. The stuff is strong, comes in a pressurized can and seals really quickly. Simple as that.

 

[vegas39]

Ok. Thanks guys, I'll get what I need tomorrow. Should I use synthetic oil?

 

[03wr250f]

yes 75-140 sythetic oil.
requires 85-140 but why not go to a slightly thinner more common oil? the main difference is pour point being like -10* vs -35*.

 

[chillman88]

yes 75-140 sythetic oil.
requires 85-140 but why not go to a slightly thinner more common oil? the main difference is pour point being like -10* vs -35*.

They're both the same (140) when they get warmed up. The 75w-140 will flow better when cold so it'll most likely net you marginally less rolling resistance and therefore help a tiny bit with mileage. I'd choose synthetic 75w-140 over 85w-140 any day.

 

[catbird7]

When I changed diff cover to Ford Alum cover, also re-filled with Royal Purple synthetic. Prior to this change my rear was completely dry, zero leaks. After changing to synthetic, within one year both axle seals & the pinion started leaking. Not a lot, but they were wet. I drained synthetic and refilled with normal dino, so far no leaks, (same pinion seal, same axle seals).

 

[Macrobb]

What weights did you go with? Synthetic and dino?

See, when you put a thinner oil in(which is mostly reflected in the 'w' number), it will flow better... and try to flow through worn seals.

I'll bet that in a few years or less, those axle seals will weep again. It's just that the dino oil you chose is thicker than the synthetic, and won't go out of the cracks so easily.

 

[chillman88]

When I changed diff cover to Ford Alum cover, also re-filled with Royal Purple synthetic. Prior to this change my rear was completely dry, zero leaks. After changing to synthetic, within one year both axle seals & the pinion started leaking. Not a lot, but they were wet. I drained synthetic and refilled with normal dino, so far no leaks, (same pinion seal, same axle seals).

What did that cover run you and do you have a part number? I looked and the cheap ones on Summit are $100

 

[catbird7]

I think there's a portion of one bottle still in garage, I'll look tonight.

What weights did you go with? Synthetic and dino?

See, when you put a thinner oil in(which is mostly reflected in the 'w' number), it will flow better... and try to flow through worn seals.

I'll bet that in a few years or less, those axle seals will weep again. It's just that the dino oil you chose is thicker than the synthetic, and won't go out of the cracks so easily.

I think there's a portion of one bottle still out in the garage, I'll look tonight and report exactly what it was.

 

[catbird7]

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[catbird7]

I'll have to look up info tonight. Bought it directly from Ford and the price wasn't too bad. Fairly certain still have the box and maybe invoice. Thinking it was around $70.00. Also powder coated mine to keep it from oxidizing. Found photo of Royal Purple gear oil, appears to be 75 / 140

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