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73 Gremlin 258..rear main seal

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idrambler View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote idrambler Quote  Post ReplyReply Direct Link To This Post Topic: 73 Gremlin 258..rear main seal
    Posted: Sep/05/2017 at 3:41pm
I have not and most likely would not...

But has anyone attempted to change the engine rear main seal with the engine in the car....

or is it even possible????

thanks 
Jim....AMCRC
Treasure Valley AMC Club, Pres
69 AMX 401/727
74 GremlinX 401/727race only
73 Matador 2dr HT 360/727
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Post Options Post Options   Thanks (0) Thanks(0)   Quote vinny Quote  Post ReplyReply Direct Link To This Post Posted: Sep/05/2017 at 4:49pm
Rockauto shows it as a two piece seal National 5111 so yes, if you can get the pan off it would be possible, although right now they are showing out of stock. Others have done it. Farna has described the procedure here before, but I can't remember the details. I plan on doing the same to my truck some day. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pdok Quote  Post ReplyReply Direct Link To This Post Posted: Sep/05/2017 at 6:13pm
Possible, did it on my 76. Difficult for me because the oil pan drop required me to lower the whole cross member to get clearance to slide it out. Also, I could not get the seal in the groove easily and almost pulled the crank out to get room for it.

I've done a Buick V8 in the car and it was completely easy by comparison. So, I must have done it the hard way. Dropping the oil pan is the hardest part by far, in my opinion.

Replace the oil pan gasket with the nice felpro one piece while you're there. Don't forget the dabs of silicone though.
76 Grem X 258/904,4.0 head/MPFI, Comp X250H cam, Hughes springs, Clifford header, serpentine swap.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 232jav3sp Quote  Post ReplyReply Direct Link To This Post Posted: Sep/06/2017 at 8:53pm
It's a straight forward and relatively easy repair to make.  Find a tutorial to watch, or read, and be darn sure you install the seal with the correct side facing the bellhousing.  If not all of that oil you just tried to keep in the engine will be on the floor!  Lol
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Greyhounds_AMX Quote  Post ReplyReply Direct Link To This Post Posted: Sep/09/2017 at 2:54pm
Sometimes the only way they will come loose is if you apply some heat. Keep some wet towels ready and a fire extinguisher handy as well. It'll make a lot of smoke before is gets gooey enough to come loose.

You'll probably want a Sneaky Pete tool as well.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote idrambler Quote  Post ReplyReply Direct Link To This Post Posted: Sep/09/2017 at 3:50pm
Thanks guys for your help....just getting info about getting it done for a new to AMC 73 Gremlin owner.....and a new member of our local AMC Club....may have a friend that will do the job for him....
Jim....AMCRC
Treasure Valley AMC Club, Pres
69 AMX 401/727
74 GremlinX 401/727race only
73 Matador 2dr HT 360/727
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Post Options Post Options   Thanks (0) Thanks(0)   Quote DaemonForce Quote  Post ReplyReply Direct Link To This Post Posted: Sep/09/2017 at 4:37pm
Unless you want to suspend it on a comealong while you're under it, don't bother. Only makes sense to drop the pan and change the rear seal when it's in a Jeep. Maybe I just have it worse because I have a Javelin and Eagle. Confused Neither one makes things easy.
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American 304 2v | FMX | AM20-3.31

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Jeep 4(.7)L S-MPFI | 1982 NWC T-5M (4.03/.76) | Dana30IFS/35-2.72
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Pdok Quote  Post ReplyReply Direct Link To This Post Posted: Sep/09/2017 at 5:47pm
On mine... unbolted motor mounts, jacked motor up until the trans bell hits firewall.  Not enough clearance for pan.  So, unbolt front crossmember and use wood wedges to force it down away from pan even more, about another 1.5 inches.  That's what it took.  Do NOT put your hand between the motor, pan, crossmember!! Unless you want the risk of crushing your hand.

The pan did not just "fall" off at that point, but I had enough clearance to wiggle it out.  I didn't try turning the crank to see if it would help move out of the way, but probably should have at least tried that idea.  I have no idea if that helps, but on other makes I know you have to get the 1st and 2nd pistons off the bottom to get the pan to slide back enough to drop.

FelPro OS34308R gasket was awesome, highly recommend it.  I assume it fits 258's of any vintage...might check that.  Two things using that gasket.  You MUST make the oil pan gasket surface perfectly flat and smooth, no burrs or wavy metal (true for any gasket surface).  You need to torque the pan bolts as recommended, and don't just go 'round the pan, make a star pattern.

I'd recommend a couple of dabs of high quality RTV on the places where the timing chain cover corners are, too.  Those areas were not perfectly level on mine.

Best of luck.  I'll never, ever do that job again with the motor in!!  Ever.

Oh, and if you're planning to do anything else, like cam, head, whatever, then just bite the bullet and pull the motor, or motor/trans.  You have to take the front grill and stuff off anyway, and the amount of work to swap a cam leaves just a few more steps to pull the motor and trans anyway.  Depends on your level of pain tolerance, and what you're doing to the motor next, I guess.

76 Grem X 258/904,4.0 head/MPFI, Comp X250H cam, Hughes springs, Clifford header, serpentine swap.
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