Rtv Sealant On Rear/front Diff

[mints33]

Are there any RTV sealant that should NOT be used on the diffs? I got a tube of the copper stuff for it's got the highest heat rating, but just wanted to make sure it's safe to use on top of a gasket. Thanks much for any help!!!

[minibike132]

I wouldn't put any on the gasket, it isn't necessary.

[mints33]

I wouldn't put any on the gasket, it isn't necessary.

 

 

What would you use for a gasket sealant? I've got a felpro gasket and it calls for gasket sealant.

Is felpro not a good brand to use?

[minibike132]

I don't really know the answer to that I've never used one. I can tell you that whenever I have to remove a diff cover and it has sealant on it I'm likely to throw wrenches. If it is that crappy a gasket that it would require rtv then I would get a better one. Even a GM one can't be that expensive. I'd be willing to bet the price of the gasket + the rtv you should use with it is more than an OE gasket.

[crepitus]

I wouldn't put any on the gasket, it isn't necessary.

i am with you. When i changed mine i couldnt even find a gasket. just used rtv.

[minibike132]

I wouldn't put any on the gasket, it isn't necessary.

i am with you. When i changed mine i couldnt even find a gasket. just used rtv.

 

 

[pm26]

There are some cars, like older Mercedes cars that do not use any gaskets for the differential covers, only a bead of RTV. Of course, in this case, using a sealant is required. As mentioned by others in this thread, you do not need to use sealant with the paper gasket, but you could use a small amount brush-on liquid sealant. I use this type on paper gaskets on my boat (e.g riser to manifold, thermostat housing). I guess a small amount of RTV is OK on a paper gasket as well. High temperature (red) or very high temperature (copper) RTV is OK in this application.

[MS3DALE]

I know two of the GMT400 trucks I had ('94-'97) that had the "F44" Heavy-Duty chassis pkg. with the 9.5' rear-end did not have a gasket for the rear-end cover,you had to use RTV sealant.

[minibike132]

I know two of the GMT400 trucks I had ('94-'97) that had the "F44" Heavy-Duty chassis pkg. with the 9.5' rear-end did not have a gasket for the rear-end cover,you had to use RTV sealant.

 

I agree if that is what is called for. The op has a 1500, I don't know what diff he has but none of the light duty apps call for anything other than a gasket. You are right though some apps call for rtv only. Not all RTV is created equal though so I would look at what is called for and use something equivelent if not the called out number.

[pm26]

Here is one example why using a sealant with paper gaskets is not such a bad idea:

 

I used to own a 1995 Nissan SE V6 4x43 pickup which I bought new and kept for 10 years. Around 90k miles, the rear main seal started leaking badly and ruined the clutch disc. It turns out that it was not the rear main seal that leaked, but rather a paper gasket on the rear main seal installation plate (the plate bolts to the engine block with the seal in it, and a paper gasket is between the engine and the plate). They did not use any sealant on this paper gasket at the factory, and after so many years, hot oil under pressure leaked under the gasket. This leak cost me $ 1,200 to repair: new clutch and rear main seal, plus the paper gasket with RTV on it this time.

[MS3DALE]

I know two of the GMT400 trucks I had ('94-'97) that had the "F44" Heavy-Duty chassis pkg. with the 9.5' rear-end did not have a gasket for the rear-end cover,you had to use RTV sealant.

 

I agree if that is what is called for. The op has a 1500, I don't know what diff he has but none of the light duty apps call for anything other than a gasket. You are right though some apps call for rtv only. Not all RTV is created equal though so I would look at what is called for and use something equivelent if not the called out number.

 

 

Yep,None of the newer light-duty trucks call for anything other than a gasket,that was just on the '88-'99 GMT400 9.5' rear-end.

And yes,not all RTV sealants are made for axle applications.

[minibike132]

I know two of the GMT400 trucks I had ('94-'97) that had the "F44" Heavy-Duty chassis pkg. with the 9.5' rear-end did not have a gasket for the rear-end cover,you had to use RTV sealant.

 

I agree if that is what is called for. The op has a 1500, I don't know what diff he has but none of the light duty apps call for anything other than a gasket. You are right though some apps call for rtv only. Not all RTV is created equal though so I would look at what is called for and use something equivelent if not the called out number.

 

 

Yep,None of the newer light-duty trucks call for anything other than a gasket,that was just on the '88-'99 GMT400 9.5' rear-end.

And yes,not all RTV sealants are made for axle applications.

 

 

That said, Jam it is my professional opinion go with what is called for in this application. I would just get the gm gasket and be done with it. Take that advice or leave it. I know that it may make sense to add some gasket sealant to a water pump gasket or rtv to a rear cover gasket but I personally do not think it makes any sense to use more than a gasket in a light duty gm differential application like the one you have there. In fact, this is fact not opinion, if you use too much of the wrong rtv you can cause dammage. That's my $.02, take it for what it is worth.

[DamageInc]

I don't really know the answer to that I've never used one. I can tell you that whenever I have to remove a diff cover and it has sealant on it I'm likely to throw wrenches. If it is that crappy a gasket that it would require rtv then I would get a better one. Even a GM one can't be that expensive. I'd be willing to bet the price of the gasket + the rtv you should use with it is more than an OE gasket.

 

That depends on the type of sealant. Some can be a bitch to remove, but most of the standard silicone based sealants will actually make a paper gasket easier to remove, not more difficult. But it will still seal bettter than the plain paper gasket.

 

As long as you don't use too much sealant (so that it oozes out and could possibly float around), it won't hurt your diff.

[mints33]

I will be stopping at the dealer tomorrow for a gasket, and compare it to the felpro, and use the better one! I will skip the RTV sealant.

 

The 1500 does not have the F44 package, so it's got the smaller diff.

 

Thanks much guys!!!