Mr. Murphy strikes again

[59 wagon man]

well i figured since the tj has 100,000 miles i would change the differential fluids front and rear. well i read the Haynes book and it says torque cover bolts to 30 ft lbs. as i did i watched the gaskets push out, so it leaks. then i go to bolt on a replacement fender , the first fender i get is damaged in shipping to i go to morris 4 x 4 i buy it in stock bolt on everything from the bottom get the battery tray back in and the bolt going into the radiator shell isn't drilled , so i gotta pull the fender out to drill the hole

 

[mde8965]

First step ditch the Hayes manual. There is a link to the FSM somewhere on this site. It’s the first sticky thread in the frequently asked questions section.

As for the diffs are you using some sort of cardboard gasket or ATV/silicone? There are several YouTube videos to show you exactly how to do it so you won’t get leaks.

As for the fender thing. That sounds like me. I usually have to do most things twice because I forget a step or try and take a shortcut.

Murphy’s law is a beaaatch.

 

[Chris]

Yes, ditch that garbage Hayes manual and download a free FSM here:
Jeep Wrangler TJ Factory Service Manuals (FSM) & Technical Documentation

 

[59 wagon man]

i used felpro gaskets and rtv ,tightened it finget tight ,let it sit for an hour ,then torgqued it like they said and watched the gasket squeeze out

 

[mde8965]

If you have to re-do it, I would use just the RTV. Just make real sure you clean any and all of the old residue off both sides of the cover and the "pig". After I scraped careful with a razor blade I used a green scotch bright pad to completely clean it. Put the RTV on there and around each of the bolt holes, then put the cover on there and followed the 1 hour thing at finger tight then the 24 hour wait before putting the fluid in to let the RTV cure. Some the RTV will squeeze out the sides, but that should be ok...

 

[59 wagon man]

i felt so good finding the gaskets , replacing the top bolt on the rear diff which was missing and the hole filled with silicone. and it leaks:bash:

 

[Rob5589]

RTV is all you need. Make sure both surfaces and bolt holes are clean and goop it on. Tighten down the cover, throw on the wheels, and fill it with oil. I have never waited more than maybe 20 mins before filling. If we had to wait 24 hrs at the shop we'd have never gotten anything done.

 

[Jorge Bolivar]

Clean up very good. Keep in mind Prep is the key.
RTV (red or Black)
Tighten down the cover on start pattern. I does it on two steps 15 Lbs torque / 15 Lbs torque.
Refill after 30 -45 minutes.

 

[59 wagon man]

sorry guess its just me and no offense meant to anyone as i understand time is money but rtv seems so shoemakerish to me .but in the infinite wisdom of guys and girls who know more than me about jeeps ill skip the gaskets and go rtv

 

[Rob5589]

sorry guess its just me and no offense meant to anyone as i understand time is money but rtv seems so shoemakerish to me .but in the infinite wisdom of guys and girls who know more than me about jeeps ill skip the gaskets and go rtv

Actually, you should be thinking 180 degrees opposite. The rtv is a far better sealer than a gasket. A typical felt/paper gasket seals by absorbing whatever liquid it is containing. No fluid, they dry out, crack, leak, etc. They also do not conform to surface irregularities. Rtv doesn't do any of that.

 

[LiftMore]

RTV only and make sure to go around the bolt holes.

 

[Head Lice]

As others have mentioned ..... preparation is the key.
Some folks use ScotchBrite or a similar product to clean the mating surfaces.
Fine steel wool works very well also. Just be sure to cover the gearset with a rag or paper, and wipe well. Wipe mating surfaces with brake cleaner.

 

[glwood]

Does anyone use lube locker gaskets?

 

[badlieutenant]

I forget who makes them but I’m going to get them when I change my diff fluids at 100k... they’re reusable rubber gaskets.

 

[Serbonze]

Does anyone use lube locker gaskets?

Yes. I think I'm on my sixth re-use on the rear Dana 44. No leaks.

 

[JeepZilla380]

Does anyone use lube locker gaskets?

Yea, I use them and on my 2nd diff fluid change with no leaks. Not a fan of scraping RTV more than once.

 

[59 wagon man]

Actually, you should be thinking 180 degrees opposite. The rtv is a far better sealer than a gasket. A typical felt/paper gasket seals by absorbing whatever liquid it is containing. No fluid, they dry out, crack, leak, etc. They also do not conform to surface irregularities. Rtv doesn't do any of that.

thinking about it with a clear head you guys are 100% correct as i have done several repairs and modifications where the gasket spec'd was rtv. guess i'm just showing my age cause i remember all the horror stories when i first heard about it years ago

 

[59 wagon man]

ok so i just looked at the torque spec chart which Chris was very helpful in posting so here is my question. torqueing the bolts as it said to 30 ftlbs caused the gasket to squeeze out ,so when using rtv due you still torque it to 30 ft lbs. thanks. prepping it isn't an issue as i have a scothbrite pad on a air grinder so it was spotless in no time and as suggested i covered the gears with a clean rag

 

[mrblaine]

How we do it and as usual, you are welcome to do it however you like, but there's a whole bunch of "knowledge" about stuff that gets repeated as "truth" that really isn't.

1- pull cover, peel off the big strings of smooshed out cured RTV.
2- scrape diff side with a single edge razor blade perpendicular to surface to get the large bits off.
3- repeat for cover.
4- apply Mopar gear oil specific RTV so that when smoothed out, it is about 1/16" thick.
5- install cover using top bolt and taking care to not slide cover sideways and smear the RTV around.
6- install rest of bolts, then tighten all of them.
7- fill with gear oil.

Here is the logic. Mopar RTV is formulated for oily surfaces, so we just spray a bit of brake cleaner on a rag and give both sealing surfaces a quick wipe. If we leave some smallish bits of RTV in the low spots by just scraping, they are doing just that, filling the low spots and that's what we want. Putting new RTV over old RTV down in the low spots doesn't hurt a thing, it got there by filling the low spot so what difference does it make? If we scrape it lower than the top of the high spots, the new layer will go into the spot and still fill it so again, what difference does it make? We never wait on the RTV to cure before we fill with oil and here's why.

The oil has a very small amount of hydrostatic pressure. Recall how much force it takes to push the RTV out of the tube through the relatively large hole you poked in the seal under in the nozzle end to get it onto the sealing surface. The oil would have to have a higher amount of force to displace the RTV in that very thin layer trapped between the two surfaces and that simply isn't possible.

The last and single most important thing that I rarely see mentioned is to take a bottoming tap and clean out the holes in the diff. Folks are rarely careful about how much RTV they get in the holes so it is possible to get a bolt started and have it "hydro-lock" on the old RTV and then break off before it bottoms out on the flange and gets tight.

Gaskets are used on gear swaps until the break in period is over and we change the oil at which point we toss the gasket and use RTV.
We can't use gaskets off road because the first time you bump the cover on a rock, it compresses the gasket, the cover springs back and now we have a leak.

 

[mrblaine]

Tighten down the cover on start pattern.

I'm assuming you meant a star pattern. I have a question. If you wanted to tighten them in a pattern that was absolutely guaranteed to cause a leak, what would it be?

Trick question because there is no pattern you can use that will cause a diff cover to leak just due to the order that you tighten the bolts in. Just make sure all of them are started in the holes and snugged down to the face of the cover before you start tightening.