With Silicone and No Gasket, Can I Tighten the Rear Cover More Later?

[dibbons]

When I had a used sure-grip installed in my '72 8 1/4 differential, I asked the mechanic if he used a gasket on the rear cover? He said, no, they don't use gaskets any longer.

Now 6 months later, I noticed a slight damp spot directly beneath the differential cover (haven't climbed under there yet to investigate). But regardless, I have a question about what to do when an area normally sealed by the factory with a gasket is sealed my a pliable type sealer (silicone, etc). Is there any point in trying to tighten a seeping differential cover if the silicone/sealant was applied months previously? I'm thinking it could just make things worse since it already took a set. Thank you.

 

[harrisonm]

If a proper bead was applied, and since it didn't leak for a while I am guessing it was, perhaps a fastener just worked loose, or wasn't tight enough to start with. I see no reason why you could not snug the fasteners a bit. Do it slowly and just a bit at a time. The silicone will be fully cured now and should be able to handle it.

 

[RustyRatRod]

Since when have "they" stopped making differential cover gaskets? We still have a whole line of FelPro cover gaskets in stock. You can look up a 2018 truck online and find a cover gasket for its application.

That said, RTV will work very well. If that's all he used and it's leaking, he did a crap job. A good bead of RTV on hat cover and once cured, you could remove the bolts and it still will not leak. I don't think any amount of tightening will fix it. It will have to be resealed. I always use a gasket though.

 

[kursplat]

if you like a gasket for that application, my answer to him would have been ""they" don't, but i do". personally, i don't use gaskets for that anymore. silicone works fine if applied correctly. now that it's leaking, you need to redo it one way or the other.

 

[TrailBeast]

Since when have "they" stopped making differential cover gaskets? We still have a whole line of FelPro cover gaskets in stock. You can look up a 2018 truck online and find a cover gasket for its application.

That said, RTV will work very well. If that's all he used and it's leaking, he did a crap job. A good bead of RTV on hat cover and once cured, you could remove the bolts and it still will not leak. I don't think any amount of tightening will fix it. It will have to be resealed. I always use a gasket though.

I agree that gaskets are still available, but I personally don't use them because they can seep oil through some of the materials.
Just use black RTV and go all the way around the cover plate face of the diff staying inside the bolt holes with a bead about the size of metal brake line (3/16) and slap her on wet.
Contrary to popular belief you don't have to wait for it to cure.

Of course this info is pointless if the leak is a pinion seal.

 

[famous bob]

Since when have "they" stopped making differential cover gaskets? We still have a whole line of FelPro cover gaskets in stock. You can look up a 2018 truck online and find a cover gasket for its application.

That said, RTV will work very well. If that's all he used and it's leaking, he did a crap job. A good bead of RTV on hat cover and once cured, you could remove the bolts and it still will not leak. I don't think any amount of tightening will fix it. It will have to be resealed. I always use a gasket though.

O`REILIES CARRIES DANA 60 GASKETS ?!?

 

[Dicer]

The shop manual shows use of a differential gasket, should it not be there. RTV sealants work great but even oils from a lonely finger or thumb print is enough for the sealant not to work. Must clean the surface with either, thinner, or your favorite carb. cleaner to seal properly. I use both sealant and gasket, just a lite smear on the gasket, clean surfaces and you are good to go..

 

[RustyRatRod]

O`REILIES CARRIES DANA 60 GASKETS ?!?

Yup.

 

[oldkimmer]

As mentioned, check to see if the pinion seal is leaking, it will run down the slippery slope and drip off the bottom right under the cover. Kim