It was time to change my front and rear diff fluid, so I went ahead and ordered some chrome covers. The website I ordered from offered a gasket for $5, so I figured it would be easier than messing with RTV. Turns out I was wrong, I have everything torqued correctly and can't get it to stop leaking. Now I have to buy RTV anyway and do everything over. Guess its like they say, do it right or do it twice.

 

Best stuff to use is the Right Stuff in a cheeze wiz can..It will never leak and you can also use it with the gasket. Regular rtv won't cut it like the right stuff will.

Dick

 

Your problem is probably the cheap Chinese chrome covers that have bolt holes punched though the thin steel with the mating surface out of square.

Replace leaky diff cover w chrome valve cover and you have a story as old as hotrodding

The gasket will do the job but not on sub par parts. For that you'll have to load the joint up with RTV and hope it makes up the gaps.

That or sell the chrome covers to a bro on Craigslist for HIS bro dozer

 

Cheap gasket + cheap cover = leak...............no brainer.

 

Just use the stuff and no more leaks ever. Ya chrome is terrible to seal..

Gasket Makers : Permatex® the Right Stuff® Gasket Maker

 

I think I'll just stick with RTV. I've used it in the past and never had a problem. I just figured a gasket was less work.

I'm not really seeing how a cheap cover will cause a leak (btw they weren't made in China). Do you have to buy a rip-off Mag-Hytec just to get a good seal? A flat surface is a flat surface, and these covers were straight as an arrow.

 

Use what you want. My 40 years experience means nothing anyway. Only try to help.
Back in the day when chrome valve covers were cool all they did is leak if they chromed where the seal was supposed to go. We used to grind off the chrome..Most silicones don't like diff fluid.or chrome surfaces ."The stuff" is a special blend that is by far superior to any other goop on the market for any gasket area. Sometimes regular silicone will last for 1/2 year and give out. This stuff is permanent.

 

Well if you're saying its specifically better for chrome, then I'll give it a try. I've never put RTV on chrome covers before, I was just saying it works fine for normal ones.

 

Obviously the key factor is to get both surfaces operating room clean, as I like to say. That being said, I've always used Permatex Ultra Black - no gasket - and never had a leak. I'm going to look into "The Stuff" however, as I've now heard several people who swear by it.

 

A lot of factors go into sealing, it's not just a matter of putting "a" gasket in and adding the bolts. There is thickness, material, flexibility of the parts, smoothness of the surfaces, flatness, potential to warp, etc, so it makes sense to me that just buying a cover and a gasket online would probably leak. They got your money and you got the leak, and they don't care. Don't forget to let that sealer set up for a while first and add it to both surfaces also.

 

I used both on mine, mainly because I didn't want to spend hours scraping off all that RTV again. So used a Felpro gasket with just a small bead of RTV, recommended by some of the folks on here actually. IMHO it's the happy medium, no leaks and if I need to open it again it won't be a 4 hour long process of scraping.

 

I have used both permatex and rtv. No real preference but I do have a tube of permatex in my tool bag behind the seat.

I also have some gasket material handy though too.

 

I've had good luck with permatex. When I changed my first diff sealI called my local mech and asked if I should buy a precut seal or use permatex. He said from his experience if you don't want it too leak use the permatex, if you want it to leak use a pre cut seal.
I ran into the same issue when I was replacing the thermostat on my diesel truck a couple of years ago, the kit came with a new precut seal, but since I don't trust them I asked the dealership if I should use some permatex also. They said there was no need to. well I followed their advice and guess what, the thermostat housing seeped. I had to drive the truck for a couple of days like that until I had time to tear everything down again. I then bought a new seal, put a smear of permatex on both sides and haven't had any trouble since.

 

That is exactly what I would have done.

The next time you run into something like that borrow an old wood chisel and heat the sealer with your torch.

 

I use no gasket. Just small bead of RVT gray. To much RVT is also bad, it will squish out, dry up, break off and find its way to a bearing and plug it up from lube eventually burning it out.


You want minimal squish out. On many machined flat surfaces I will actually just use my finger to apply the RVT in a thin film.