Permatex 80065-12PK High Tack Spray-A-Gasket Sealant, 9 oz. net Aerosol Can (Pack of 12)

had before works great to hold gaskets in place

My axle seals in my 1993 F-150 failed and leaked over my brakes, so a repair was needed. That meant draining the rear differential in order to gain access to the axle. There are many schools of thought regarding how best to re-attach the cover to the differential once the work is done. Options include: RTV only, gasket only, gasket with RTV and gasket with this high tack sealant. It seems the preference has moved to using RTV only especially in newer vehicles. That may be related to manufacturing processes and the simplicity of having an automated tool dispense the RTV as the axle moves down the line. Keep in mind that the differential is likely facing upwards during the manufacturing process to facilitate the RTV application. In the real, shade tree mechanic world, this rarely happens. The surface is vertical and presents minimal challenges, but one can still mess it up if not careful. I’ve used RTV only in my 2014 F-150 and have evidence of minor seepage. That’s on me, as it was the first time that I ever used RTV only, as that was the OEM process. In contrast, my 1993 had a gasket and likely an adhesive. It was a bear to clean, as I had to scrape its remnants from both surfaces. I replaced the fluid in 2018 and used a gasket and RTV. Reading further into the best practices, some folks commented that a gasket and RTV should never be used together. I wish I read that earlier, as there was evidence of minor seepage beyond the gasket. I then took a deep dive into the F-150 forums and found someone who had suggested using a gasket with Permatex High Tack Gasket Sealant. He noted the sealant doesn’t harden or cure, so re-servicing is slightly easier. I opted to give this a try, and I’m glad I did. I made sure both surfaces were free of gasket, grease, dirt and RTV. A light sanding on each surface was followed by a wipe with brake cleaner. Make sure the sump in the bottom of the differential is empty, or at least not near the edge, as it may wick over and drip on the bottom surface and render your seal useless. As I noted above, there are multiple suggestions as how to apply this to the surfaces and gasket. Here’s what I did. I laid the cover flat and applied the sealant to the sealing surface. The sealant has a brush. I ensured there was a good coating especially where the gasket would be in contact with the cover. I then applied the gasket to the cover. The sealant holds the gasket in place, so make sure you align the holes. This sealant is unique in that it gets stringy when exposed to air. I found it best to work quickly and not to go over areas multiple times to avoid clumps. I then applied the sealant to the other side of the gasket, that is the side that’s against the differential surface. It was just easier for me this way, as I was working on the ground. You can likely add it to the differential if you’re working with a lift. Excess towards the inside of the cover, and therefore differential, can be wiped after the gasket is laid on the cover. I carefully aligned the cover, added 1-2 bolts to hold it in place and then torqued all 10 bolts to 30 ft lbs. I don’t think there is any cure time with this product, but seeing as I had other things to do, I left the differential empty until it was my last task. That was about 1-2 hours later. There are no leaks, so this will be my preferred method going forward with this truck. Good stuff.

Great product and arrived on time

Used primarily to rebuild my outboard lower unit. The gasket that seals the lower unit to the boat is sketchy at best to fit without moving. This stuff work great to hold the gasket in place while it worked the lower unit back into the boat.

It’s good for tacking gaskets in place. It’s more of like a rubber cement. I like RTV silicone for most gaskets sealer.

I debated on this or your regular silicone RTV for my rear differential with a gasket, but seeing it here for the price along with the benefit of it being easier to remove with solvent, it was a no brainier for me. It works great for seals and gaskets without the silicone "bonding" to the metal for the next guy down the road to clean up. Best of all, it remains tacky even when dry, so it can be "reformed" if needed vs RTV silicone. Another upside is that it is in a sealed can vs the RTV tubes that always have a tendency to dry up due to the plastic caps always cracking, forcing me to buy more The only downside is that it is so tacky, it can make a mess if you aren't careful, leaving "spider webs" everywhere. Try to work in a cooler, room temperature environment if you can vs 95 F weather.

Very tacky and worked great for keeping the gasket in place. A bit expensive but solves a problem.

This is a step that most DYI types miss. If you are like myself and prefer to use a paper gasket instead of the gasket maker in a tube then you should consider this product. You spray both sides of your gasket with this adhesive and apply the gasket to your well cleaned surface. Align all the bolt holes perfectly. Wait 5 minutes then install your cover. This will assist in preventing any leaks and really helps on vertical surfaces like differential covers or semi-vertical surfaces like valve covers.