RTV sealant vs. gasket

[maps]

I have already done a search on this topic prior to posting. I am getting ready to change rear differential fluid. What do you guys prefer to use: RTV sealant or just a new gasket or both? Any advice or tips for someone who has never done this on an XJ. Vehicle is a 1999 XJ. Thanks in advance.

[richasco]

If you use RTV be very careful not to use too much. The excess can be pushed inside the cover. When it breaks off, it does a great job of clogging the bearings. I picked up an 8.8 to put in my Wranlger the previous owner had really glued the cover in place. After 1,000 miles I had a nicely ruined pinion bearing. Plus just look at the cost $3 for a nice gasket vs. $6 for a tube of RTV.

[GrayT]

Not to mention how annoying RTV can be to clean off if its been on there for awhile.

I'm using a LubeLocker gasket on my D30, too bad there isn't one for the C8.25 :(

[Rick Anderson]

RTV and a Gasket, you'd think you got the best of both worlds, NOPE. The RTV lubes the gasket real well and the gasket won't hold in place when crushed, the gasket will squeeze out from inbetween the bolts, be deformed and leak.

I've tried it several times with an Auto Trans Pan Gasket, the combo of Gasket coated with RTV leaked everytime, while the plain gasket never leaked. I'd be surprised if you didn't get the same result with a Diff cover gasket.

Cork Gaskets were the worst, some of the fiberous/rubberized gaskets would hold their shape better, but they still leaked if I coated them in RTV and then torqued the cover down. You can see the gasket squeezing out between the flange and the cover.

They make several different GASKET DRESSINGS, I've tried some and they seem to be very effective. A gasket dressing is designed to coat a gasket, hold it in place while you put the components back together and help the gasket seal better. The Dressings I've tried worked well, it was the MOPAR HEADGASKET SEALANT, which is really just a spray can of really good gasket dressing, I kept using the left over can on other gaskets (Since its says right on the can it can be used for them as well).

You want something sticky & tacky as soon as its on the gasket, not something that is rubbery and fluid like RTV is before its cures.

Loctite has there new WAX Sticks for threads, Blue & Red Threadlocker, Copper & Silver Anti-Sieze and Pipe thread sealant. They also have a stick out that is for Gasket Dressing, I haven't seen it in the stores yet, but I'd like to try that.

[Rick Anderson]

OH BTW, when you see its recommended to use RTV with gaskets, its always a tiny bead in sharp corners, to go along with the gasket, not coat the entire gasket in RTV. Valve Cover and Oil Pan Gasket often aren't flat, they have to fit over a round raised portion, there may be sharp corners where the raised portion comes up out of the flat. Its those sharp corners that gaskets sometimes pull back from when they shrink a little and the oil leaks, a bead of RTV in that sharp corner prevents the leak.

[Wayne Sihler]

Not to mention how annoying RTV can be to clean off if its been on there for awhile.

I'm using a LubeLocker gasket on my D30, too bad there isn't one for the C8.25 :(

YES,one is available for the 8.25 Chrysler rear.A new item,It may not be listed in the catalogs yet.
Wayne

[Kejtar]

I have already done a search on this topic prior to posting. I am getting ready to change rear differential fluid. What do you guys prefer to use: RTV sealant or just a new gasket or both? Any advice or tips for someone who has never done this on an XJ. Vehicle is a 1999 XJ. Thanks in advance.
RTV, lay a thin bead and then let it dry about 10 minutes, put in on and finger tighten the bolts and let it sit another 10 minutes and then torque to spec. Never had a problem cleaning nor removing.

[Rick Anderson]

RTV, lay a thin bead and then let it dry about 10 minutes, put in on and finger tighten the bolts and let it sit another 10 minutes and then torque to spec. Never had a problem cleaning nor removing.
The secret may be to make sure the thin bead is so thin that when the RTV is squished outward, that it does not squish past the edges of the gasket.

I've put enough of a bead on the gasket that RTV squished out over the entire surface of the gasket, thus coating the entire gasket, even giving the gasket hours to sit, before torquing, it still squished out under the clamping of the cover to flange.

If, the RTV only spreads to part of the gasket and leaves a good part of the gasket dry, the gasket probably has enough friction to hold its shape and not squish out.

So, use only a tiny bead like Kejtar says, I may try that technique.

[Kejtar]

The secret may be to make sure the thin bead is so thin that when the RTV is squished outward, that it does not squish past the edges of the gasket.
I didn't say anything about the gasket... why even bother with gaskets? I put the RTV directly onto the cover.

[Rick Anderson]

I didn't say anything about the gasket... why even bother with gaskets? I put the RTV directly onto the cover.
DOH! You didn't did you.

I'm old fashioned, I'd prefer the gasket, I've only tried the RTV only once, and it did work fine, but I usually use a gasket especially if its something I pull several times like a auto tranny pan.

[PETEY]

RTV, lay a thin bead and then let it dry about 10 minutes, put in on and finger tighten the bolts and let it sit another 10 minutes and then torque to spec. Never had a problem cleaning nor removing.

X 2

[Kejtar]

DOH! You didn't did you.

I'm old fashioned, I'd prefer the gasket, I've only tried the RTV only once, and it did work fine, but I usually use a gasket especially if its something I pull several times like a auto tranny pan.
Well... lets not confuse the issue here: question was about diff covers. In general I agree: things like tranny pan, valve cover and so one deserve a gasket.
On the diff covers though I like RTV better as it seems to hold better especially if the diff gets whacked/dragged over a rock.

[SuperRA]

This was on my oil pan, but i just recently tried to remove it and the 19yr old gasket was soooo stuck that my pan got all bent up when trying to remove it. At first I thought it was RTV but later found out it was a gasket. I'm gonna use this sealant from permatex called "The Right Stuff" when re-installing it. I've used it on several other items and haven't had a problem. I have had gaskets (no RTV added) start to leak after a while.

[dynamite44]

i use gaskets. its not that i've had bad luck with RTV, because i've had it work one out of the two times i've used it, i just hate the stuff.
my local advance stocks D35, D30, and D44 diff cover gaskets in house, so i don't need RTV. RTV is really messy and doesn't allways work. i much prefer a nice paper/fiberous gasket. no goop, and it allways works. never had one leak. can't say the same for RTV.
if you've got a C8.25, advance can special order you one of those. they come in the next morning.

[Kejtar]

This was on my oil pan, but i just recently tried to remove it and the 19yr old gasket was soooo stuck that my pan got all bent up when trying to remove it. At first I thought it was RTV but later found out it was a gasket. I'm gonna use this sealant from permatex called "The Right Stuff" when re-installing it. I've used it on several other items and haven't had a problem. I have had gaskets (no RTV added) start to leak after a while.
The right stuff?????? You're nuts!!!! I have it for emergency repairs only. WHen I sealed a diff cover with it I bent it when trying to remove it. It's like a super sealing, never remove version of silicone gasket makers! For diffs I recommend the plain red gasket maker.

[crocket32]

Gasket all the way all the time!!

[87manche]

I used Plain red RTV on my diff covers. I've never had a problem getting it off, razor blade works just swell.
For other things it's a gasket, with the white gasket dressing. Dressing gets tacky, then you lay the gasket in place and it doesn't stop, works wonders for long ones like a valve cover gasket, since it's usually a pain to keep in the right place while wrestling with the valve cover.

[metalgearxj]

gonna chime in here for both depending on where it's going. for diff covers i like right stuff sealant. you can run a small bead around, put the cover in place, fill it and drive off. great for a trail fix if need be. my old scout had leaky valve covers and they were a bear to get straight after the PO had cranked down on the bolts. got em as straight as i could, then used the right stuff. no leakage now. i did get lube lockers for my scouts D44s as i think they will be coming off more often (even though they claim not to be reusable). right stuff is pricey, but you can do diff covers, valve covers and a ton of other stuff with one can if it doesn't sit too long. did my rear diff cover 2 weekends ago, will do the front this weekend.

[SuperRA]

The right stuff?????? You're nuts!!!! I have it for emergency repairs only. WHen I sealed a diff cover with it I bent it when trying to remove it. It's like a super sealing, never remove version of silicone gasket makers! For diffs I recommend the plain red gasket maker.

Right stuff is what the OEM uses. When I took off an oil pan (different car) with similar stuff, it was fine, never a leak yet. I just had to clean it off and re apply it. However, my oil pan on my 4.0L got all bent outta shape just from a paper gasket. I had to use two long screwdrivers and it took over 3 hours to remove! But I do agree that actual gaskets have there place. I'm not gonna use right stuff on the valve cover or intake etc.

[Kejtar]

Right stuff is what the OEM uses. When I took off an oil pan (different car) with similar stuff, it was fine, never a leak yet. I just had to clean it off and re apply it. However, my oil pan on my 4.0L got all bent outta shape just from a paper gasket. I had to use two long screwdrivers and it took over 3 hours to remove! But I do agree that actual gaskets have there place. I'm not gonna use right stuff on the valve cover or intake etc.
Don't take me wrong: I carry right stuff with me on the trail, but I will not seal a diff cover @ home with it again. This stuff is too strong for it's own good ;) The upside though is that you can put it over dirty surface and it will still seal and on top of it it sets faster.

[LOWTECH]

Both, like wearing a belt & suspenders at the same time, not needed but guarantees your pants don’t fall off.

[Ramsey]

Both, like wearing a belt & suspenders at the same time, not needed but guarantees your pants don’t fall off.
:laugh: you gotta be old:D

i've only used rtv and i hate the stuff, i have had some fast change gaskets sitting here for a while and the next time i crack my cover open i'm gonna give them a shot

[LOWTECH]

Yep