What Sealant To Use On Differential Drain Plugs?

[Fitz98]

What sealant should I use for the threads of my differential fill and drain plugs?
Changing the fluid in my front Differential with 75W90 Gear Lube.

 

[JMJNet]

Depends on what kind of car or truck?

 

[Chris142]

What kind or thread? Pipe? Straight with a gasket?

 

[930.engineering]

commonly none

 

[Fitz98]

98 Expedition 4x4, front differential.
I don't know what threads, but no gasket. Just 3/8" square hole for install. I assume it is a pipe thread.
I see some say to use teflon tape and one video I saw said hi-temp thread sealant.

 

[Big E]

I've used teflon tape or teflon paste on pipe plug types. Keeps them from weeping.

If the plug uses a gasket or washer, then nothing.

 

[spasm3]

https://www.amazon.com/Rectorseal-23710-4-Ounce-Thread-Sealant/dp/B000BKXGXM/ref=mp_s_a_1_17?dchild=1&keywords=liquid+teflon+thread+sealant&qid=1632366410&sr=8-17

 

[Dyusik]

I have never used anything but the drain bolt on anything. The only thing that ever leaked was the rubber plug that came on the equally glorious Dana Turdy-5. I even reuse the crush washers indefinitely just to see if it leaks. Nope. lol.

 

[FowVay]

On my Nissan Frontier (2017) the factory service manual states to use Permatex Ultra Grey RTV silicone sealant on the fill plug. The drain plug uses a crush gasket so it doesn't require any form of thread sealant.

 

[zeky]

Unless the design uses some sort of gasket, use none. Most every plug like that has special cut threads that seal it up when tightened properly. Get tight, but do not overtighten or you can damage those special threads

 

[vavavroom]

Conical threads should seal tightly but you can add Permatex High Temperature Thread Sealant. If there's no washer or gasket on the plug the threads are conical.

 

[RooflessVW]

Permatex

Proven and Reliable OEM Partner. As a leader in supplying automotive sealants, Permatex offers superior R&D, production, distribution capabilities and more.

www.permatex.com

 

[BlueOvalFitter]

None needed..........that I know of.

 

[ecotourist]

I look at a bit of oil staining around the differential fill plug as one sign of a well maintained vehicle.

 

[nthach]

I’ve used Teflon-containing pipe dope(Oatey Great White, Rectorseal T+2) for my drain plugs if need be, unless Loctite 242 or their PST anaerobic pipe thread sealant is called for.

 

[ekrampitzjr]

My Ranger has a differential fill plug, but no drain plug. The fill plug has tapered threads. When I got it off, the red factory sealant was still in the threads. After changing diff fluid, I just reinstalled the plug as it was without tape or sealant, but made sure it was as tight as it had been before breaking it loose. Believe me, it had been tight.

The reasoning for using nothing on the threads was that the sealant remnants would be enough and the fill plug is not normally bathed in oil on its inside surface as an engine oil pan drain plug would be. If the diff had had a drain plug, I would have used something on the threads, probably Teflon tape.

 

[Lubener]

My Ranger has a differential fill plug, but no drain plug. The fill plug has tapered threads. When I got it off, the red factory sealant was still in the threads. After changing diff fluid, I just reinstalled the plug as it was without tape or sealant, but made sure it was as tight as it had been before breaking it loose. Believe me, it had been tight.

The reasoning for using nothing on the threads was that the sealant remnants would be enough and the fill plug is not normally bathed in oil on its inside surface as an engine oil pan drain plug would be. If the diff had had a drain plug, I would have used something on the threads, probably Teflon tape.

Shouldn't have to use anything as the plug threads are tapered as you mentioned... Teflon tape might ease in removal for the next time. If the plug leaks, it's likely that someone overtightened it, distorting the threads. They don't have to be very tight.

 

[Astro14]

What did the factory use?

 

[Kira]

On 2 butchered oil drains (the pan's side-it appeared the drain plugs were OK) I used Permatex Ultra-Black.

I didn't use much and the stuff worked fine. I suspect the aluminum pans' threads were stripped by gorillas posing as mechanics.

 

[atikovi]

Have used this for years if it needed it or not just for insurance.