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  #1  
Old 05-12-2001, 03:35 PM
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UnkleMunky UnkleMunky is offline
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Picked up a gasket for my rear diff(front is supposedly the same) for my '78 J10 (dana44) today. Store only had one, so that's all I got. About $5.50 for the puppy. Got to thinking then that I have some of that "rolled"(comes in a roll) gasket material that you cut your own from. It looks to be the same thickness as the preformed one I got. Was wondering if it might be ok to use this cut-your-own stuff here? I was kinda thinking maybe to use the store one for a template and trace it out(then X-acto cut) a duplicate(or two, or more!), and use the dupes instead. Got the material....would just need to flatten it in a book for a day or so first. Is this a good idea or should I "really" make sure I stick with the preformed ones?

Also....in reading the install tips from the preformed gasket(fel-pro), they say to aid proper aligning of the gasket to put a "thin coat of gasket sealer" such as (their brand), "to both sides of the gasket(s)". Most of my experience has been to use either sealant OR a gasket, but not both. Is their recommendation right, or do I use one or the other? What's best? Also...if one is to use sealant, what "type"(color, rating, brand) is best?

PS....am removing the rear diff cover to inspect the interior condition, so draining and replacing gasket is necessary here. Am considering doing front one while I'm at it too.

Oh...one more thing...was told 75W90 "synthetic" was the grade of synthetic to use if I'm going that route. Sound right? It usually takes 80W90 dino! Would like to go synthie in both diffs, but would have to buy some jugs of it, whereas I already have dino 80-90, so not sure the route.....but still wondering if the 75W90 would be the right "juice" to feed my diffs!?!

Thanks for any input....

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Michael(UnkleMunky)
'78 J10: 258, 4 speed, longbed, topper
'76 J10: Honcho, 360, TH400/QT
'89 Plymouth Reliant(PluggerMobile)
J-Pages(some of my auto pages)
unklemunky@eskie.net
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  #2  
Old 05-12-2001, 04:09 PM
Matt W
 
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ok, ive only rarely used silicone sealant, because in my experience and observation, it doesn't seal like i think it should. plus, even though it leaks, it almost takes an act of God to get all the little bits off the surfaces when you need to next tear into the thing. i would just get another preformed gasket, i haven't ever really made my own out of gasket material, so i wouldn't personally recommend it, but if someone else out there has done it they might recommend it...as far as the synth vs dino oil...it should say what it is equivelent w/ on the bottle...i run synth oil in my engine and would recomend it simply because its just a better, albeit more espendy, product. some say dino oil's hot lubricating properties are compromised somewhat by the multi viscosity additive. full synth is naturally formulated to be multi vis and it is more efficient. i use the quack-r-state full synth, its like 3.50 a qt, but i've had mine in for 3000 mi and its still gold on the dip stick., course i leak a qt about every 750 to 1200 miles but when i used dino penzoil, i made less pressure, and it was darker when i changed it than this stuff is. i still change motor oil approx every 3 - 4000 mi but the last 2 times it was the q-state stuff, and the all the stuff in the prior 12 - 14000 mi was penz multi vis. I've had the oil leak since day one of the new 401 being installed 20-23000 miles ago. cool hunh?
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  #3  
Old 05-12-2001, 04:37 PM
Chiefly77 Chiefly77 is offline
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I use the sealant never had a leak...you have to clean the surface really good first. As far as the problem with it not coming off good when you have to change it again, a good gasket scraper has always worked for me. I'm not saying that a sealant is better than a gasket, just that its always worked for me. I use blue gasket maker. I guess its the about the same as the black silicon just might not have the same heat rating.

------------------


Charlie Nimitz
'77 Cherokee Chief W/T
360/TH-400,
QT w/low range
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  #4  
Old 05-12-2001, 05:19 PM
PAJEEPER PAJEEPER is offline
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I would use both gasket and some silicone sealer. I think that would give you the best of both. I prefer the ultra blue or copper silicone. I thinks its better than the rest. As for synthetic, never used it yet does it really make much of a difference in the diffs? I'm probably gonna run synthetic in my 360 though.
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  #5  
Old 05-12-2001, 05:31 PM
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Cecil14 Cecil14 is offline
 
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Don't know much about the oil here, but as far as the sealer and the gasket, I would use both. You don't need to use a lot of the sealer, just enough to get it to stick to what your putting it on, that way you can stick it on, and put the cover on. I've got some orange sealer, but I don't think it makes much difference unless you get into some high temp spots like the engine.

Hope this helps,
Anthony

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1983 J-10/258I6/T-176/NP208/Factory Brush Guard
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  #6  
Old 05-12-2001, 11:17 PM
joe joe is offline
 
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You can use sealant on a diff gaskets so long as they aren't cork gaskets. If you make your own gaskets I'd use sealant on both sides. I'd also stay away from any of the silicone sealers and go with the 04 type from ThreeBond Co. It's sold at practically all Jap MC shops under various names like Yamahabond 4, Hondabond 4 etc. It's expensive but works excellent and will stay somewhat soft almost indefinately. I use it on literally everything and this goop even keeps old Harleys and Triumphs from leaking(not a small feat by any stretch).
The weight syn gear lube you mentioned is what you need if you want to change to syn lube. You could also go the next weight higher if you're in someplace like AZ or do a lot of towing.

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63 2-dr Wag, 73 J-4000, 82 CJ-8
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  #7  
Old 05-13-2001, 01:10 AM
Mud Thrasher Mud Thrasher is offline
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It's alright to make your own gaskets. I do it religously. But, it is a good idea to use the one you bought for a template. It makes it alot easier plus it's cheaper to make it yourself then to pay someone else to make it for you. Also, I like to use a Little bit of gasket sealer to hold it in place when putting it all back together.

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'78 Chief 360/quadra-trac
D-44 f&r/3.55 r&p/31x10.5x15 G/Year Mt's
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  #8  
Old 05-13-2001, 04:16 AM
reddog reddog is offline
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Be sure to get the "posi" additive if you've got the "Trac-Loc" differential. Also a 1" wood chisel makes a great gasket scraper.

Kerry

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  #9  
Old 05-13-2001, 06:21 AM
WillyPete WillyPete is offline
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i just changed out the lube in both diffs (AMC20, D44). cork gasket went in the 20, rubber went in the 44. 80w90 dino in both, sealed the outside of the diff cover with blue RTV. i use vaseline to stick the gasket to the diff case before i put the cover back on.

this was my first time doing this. did i do anything horribly wrong? everything seems to be running about as smoothly as before, so i'm assuming it's all kosher.

thanks

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"Sugar Magnolia" '86 Grand Wagoneer 235/75R15 Wrangler AT/Rs, np229 x-case, bone stock otherwise
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  #10  
Old 05-13-2001, 07:28 AM
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UnkleMunky UnkleMunky is offline
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Thanks for the input, gang! Wanted to reply on a couple points.

1) To PAJEEPER who asked what difference it makes using synthetics in the diffs. I don't know "for sure" but from all my reading on synthetics, I have heard that running synthetics in your "driveline" versus your engine can actually give you BETTER fuel/power improvement than in the engine alone. Going synthetic all around would be "ideal", giving you the synthetic advantages in all places, of course. Though I can't say for sure, I'd gather the reason for this is that synthetics really cut down on the "friction" where you use them. Since your diffs(and tranny/t-case if you have manual/gear) do a lot of "churning" it would make sense that reduced friction there would mean more engine power would go directly to the wheels....instead of losing it along the way to get to the end location. Since I have a T-18 and D-20 in this rig as well, I was kinda thinking of converting over to synthetics in the gears boxes and diffs as I change stuff. If I do this at all 4 locations, hopefully it will make an improvement there, AND maybe help better protect the parts inside better than dino might. Again, not sure if this is all "accurate", but the "friction" issue makes a lot of sense to me. I'm not changing the engine over(at least not yet), as I do have a slight leak around the valve cover gasket. When I get to changing that and make sure there are no more leaks, then I will think it, but don't want to make the problem worse right now! Also, wouldn't mind seeing if the driveline only changeover makes a difference like I've read!

2) I know I have black high temp RTV right now(just did a tranny filter on my '89 Reliant and needed it there), and I think I have some Gold(orange) sealant. I might use the gold on the gasket for placement as you all suggest. That sound all right?

3) No, it's not a Trac-lok....just plain old "get you stuck in 2wd REAL easy" type! So, plain ol' juice should be fine. Thanks for the tip though....never hurts to be reminded of that when it's important!

4) WillyPete: Hmmm....vaseline on the gaskets...never heard of that, but if it worked, and keeps working for ya, guess maybe it, well, works. I'd definitely keep an eye on the situation to make sure you don't have any leaks, and also check fluid now and then to make sure it's still topped off. Sealant on the "outside" of the cover? Not sure what you mean? Again, though...if everything's working, just keep an eye on it until you're pretty darn certain it's staying that way. If ya got it licked for now, that's good!

Thanks again for the input!

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Michael(UnkleMunky)
'78 J10: 258, 4 speed, longbed, topper
'76 J10: Honcho, 360, TH400/QT
'89 Plymouth Reliant(PluggerMobile)
J-Pages(some of my auto pages)
unklemunky@eskie.net
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  #11  
Old 05-13-2001, 07:53 AM
PAJEEPER PAJEEPER is offline
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Oh I see now, thanks for the explanation munky. There is alot of gears and bearings that contact in the diffs, trans transfer case. I could see how it would make alot of drag from the friction. Might even free up a little mpg, but it surely is better for the gears.
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  #12  
Old 05-13-2001, 08:42 AM
WillyPete WillyPete is offline
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http://albums.photopoint.com/j/View?...e=0&re s=high

the RTV actually goes on the diff cover, but you can see where it would end up on the diff housing.

------------------
'86 Grand Wagoneer
Sugar Magnolia
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  #13  
Old 05-13-2001, 10:31 AM
UnkleMunky's Avatar
UnkleMunky UnkleMunky is offline
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<BLOCKQUOTE>quote:</font><HR>Originally posted by PAJEEPER:
Oh I see now, thanks for the explanation munky. There is alot of gears and bearings that contact in the diffs, trans transfer case. I could see how it would make alot of drag from the friction. Might even free up a little mpg, but it surely is better for the gears. <HR></BLOCKQUOTE>

BINGO! At least that's what I've read....and it does seem to make sense to me too. And, yes, if there is less friction, you should see a little more "power" as less is lost along the way, thus, with more power, you should not have to work the engine "quite" as hard to do as much as with more friction.....so, in the end, you "should" get a little more power AND a little better "mpg"....at least in theory. I hope theory works out to be real there! I've been getting a good 16-18mpg in regular 2wd road driving of the '78 J10, and if I can squeak out a couple more mpg, that would be super duper. 20mpg is my "dream" for this rig right now, but I wouldn't mind going over that either!

Haven't even done more than plugs for tuneup on the thing, need new exhaust(though I have current MickeyMouse system patched pretty well), and would like to do this changeover in the gears to synthetic. Fix up the engine leakage(looks like just valve cover gasket, but not sure), and maybe consider going to synthetic there too, and see how it does. "Maybe" a TFI ignition upgrade. Oh, newer tires too...mine are pretty well worn out. Maybe when I actually get more of this done, I'll be getting even better mpg! Would love that!

WillyPete: Thanks for the cool pic....super description that way! Is that an AMC20 in the pic? My gasket has holes in the gasket for the bolts, and isn't round like that. Did the directions for the AMC20 say to go about it that way? Your descriptions makes sense to me now....thanks for the pic....really helped! Take care....



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Michael(UnkleMunky)
'78 J10: 258, 4 speed, longbed, topper
'76 J10: Honcho, 360, TH400/QT
'89 Plymouth Reliant(PluggerMobile)
J-Pages(some of my auto pages)
unklemunky@eskie.net
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  #14  
Old 05-13-2001, 10:40 AM
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irbob irbob is offline
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Gaskets:Be our hero and make your own gaskets. I have made plenty of gaskets for axle end caps on 2.5 and 5 ton axles out of manila folders as well as diff covers. Put the gasket material over the surface that will get the gasget. In your case the diff with cover removed. With a small ball peen hammer gently tap (with the ball end) where the bolt holes are. (you may not have to punch the holes out)Using the hammer and edge of the hole like a sissor the hole will punch out. Then tap around the exterior edge of the diff and remove the outer part of the material. Then the center being carefull around the bolt hole areas.

Silicone: I prefer copper forma gasket. (both sides)It works for a wider range of applications and you need it for high temp jobs anyway. I don't like to have a bunch of different kinds of stuff laying around if one thing works. Two reasons to use it. For a better seal and for installing the gasket. I think more people use it for the installation purpose than the sealing side. It's easier to put it on hard surfaces cuz the gasket moves around more. Put some on the lid and then put the gasket on it. This keeps the gasket in place for installation. Whatever sealer you have will work for the diffs. I would us up what you have first instead of spending more cash.

Note: Forma gasket can be used by itself without a gasket material. Just let it set up over night before driving. Been there done that to.

Cleaning off Silicone: I use a drill armed with a wire wheel. Zipps it right off along with rust and other crudy stuff. I also clean the surfaces with Acetone to get the oils off.

Gear oil I would use what you have to get ridd of it. On the next servise put the synthetic stuff in which I think is a great idea and the 75-90 should do the job.

This is just stuff that works for me so I hope some of it can help u out. Later, Bob

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  #15  
Old 05-13-2001, 10:41 AM
WillyPete WillyPete is offline
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oh yeah... my Dana 44 gasket had holes for the bolts. the AMC20 gasket was just a cork ring.

yeup, that's an AMC 20. that's the first diff i ever popped open; oi vey, it was a beautiful sight.

take it easy y'all, i'm off to mow lawns (why can't they just pave those things?).

------------------
'86 Grand Wagoneer
Sugar Magnolia

[This message has been edited by WillyPete (edited May 13, 2001).]
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  #16  
Old 05-13-2001, 10:44 AM
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irbob irbob is offline
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Question

Is the AMC20 the same as the AMC 8 7/8"?

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  #17  
Old 05-13-2001, 12:32 PM
WillyPete WillyPete is offline
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yeup, 8 7/8 or 8.875 just refers to the diameter of the ring gear; much like ford measures their axles (e.g., 7.5", 8.8", 9", 10.25").

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  #18  
Old 05-14-2001, 12:47 AM
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irbob irbob is offline
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Thanks for the information WillyPete........hey, I have an AMC20!!!!

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  #19  
Old 05-14-2001, 01:37 AM
joe joe is offline
 
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<BLOCKQUOTE>quote:</font><HR>Originally posted by WillyPete:
i just changed out the lube in both diffs (AMC20, D44). cork gasket went in the 20, rubber went in the 44. 80w90 dino in both, sealed the outside of the diff cover with blue RTV. i use vaseline to stick the gasket to the diff case before i put the cover back on.

this was my first time doing this. did i do anything horribly wrong? everything seems to be running about as smoothly as before, so i'm assuming it's all kosher.

thanks

<HR></BLOCKQUOTE>

Nah so long as it's not leaking ya done good. Generally you don't seal cork gaskets because it's their function to soak up some oil and swell up to make the seal. More critical on valve cover and pan gaskets than on diff covers.
So far as getting gaskets to stay in place during assembly use some fine sewing thread to tie the gasket to the bolt holes. This works especially well twisting and turning oil pans into place. Just leave the thread in when you're done, won't hurt a thing.


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-joe
63 2-dr Wag, 72 J-4000, 73 J-4000, 82 CJ-8
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  #20  
Old 05-14-2001, 03:17 AM
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OBX-AUTOMOTIVE OBX-AUTOMOTIVE is offline
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GASKET'S,GEE, IF I HAD A PENNY FOR EVERY GASKET I MADE WHILE IN THE COAST GUARD I COULD RETIRE. OH! I'M RETIRED!! I MADE A GASKET ONE TIME, FOR A OIL LINE TO A NEW BLOWER,MADE THE HOLE'S FOR THE BOLT'S BUT NOT FOR THE OIL HOLE,GUESS WHAT? BOOM!!! SO WHEN MAKING GASKET'S, BESURE TO MAKE ALL THE HOLES!! THE ENGINE THE BLOWER WAS ON, WAS A V-12 DIESEL.. IT HAD TWO BLOWER'S ON IT,AND IT TOOK TWO PEOPLE TO CARRY ONE ROD AND PISTON! THE BABBIT ON THE CRANK WAS TWO INCH'S THICK. WHY, I'M I TELLING YOU THIS? I HAVE NO IDEA, WHY!! WHAT DO YOU THINK, OF A TILT FRONT END, FOR MY WAG ??? THE LAST TILT FRONT I MADE WAS ON A 52 FORD PU,IT WORKED GOOD.MAKES IT EASY TO GET TO THE ENGINE. GEMOBX/77/401


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