Replace rear main in car? 360LA -74 Challenger Automatic

[Scooter]

I was in denial for a few months.. kept telling myself it was the dizzy o-ring causing the oil spots in the drip pan. Reality is it's the rear main leaking. Anyone onboard swapped one out in car?  I did one in my 70 with a 383 Charger back in the day, wick style old seal fought me for a few days. This 360 LA was rebuilt in the last decade so I imagine it's got a newer style 2 piece neoprene seal. Looks like you can drop the pan far enough to get access to the rear main, not sure if the oil pickup gets in the way of moving the pan around or the drag link must come out. Be interested to see what folks have done.

[Chryco Psycho]

Yes it can be done , the center link has to be disconnected to swing out of the way , the oil pan will drop out & the pickup & Pump can be removed then you can get the rear main cap out , obviously the top 1/2 of the seal is the most difficult to replace

[Scooter]

Yes it can be done , the center link has to be disconnected to swing out of the way , the oil pan will drop out & the pickup & Pump can be removed then you can get the rear main cap out , obviously the top 1/2 of the seal is the most difficult to replace

Thanks! As I suspected. I recall having to loosen all the mains on my 383 to get the upper portion of the old wick style seal out. Which side of the drag link is easier to disconnect? Power steering on driver side and pitman arm on the other.

[Chryco Psycho]

First check the oil pressure sender carefully , don't ask !!
passenger side can be easier to disconnect because if the idler will not separate easily you can just pull the bolt & swing the idle out of the way as well .
If you have a rubber seal in there usually you can push one side up & grab the other end with small vice grips or needle nose & rotate the seal out without loosening the mains at all , just be careful sliding the new seal in as the sharp edge of the engine block can peel the back off the seal , seal kits used to supply a small nylon piece you can slide into the block as you slide the seal in protecting the outside edge of the seal .

[Scooter]

First check the oil pressure sender carefully , don't ask !!

^^^ First place I checked... was REALLY hoping one of these 2 was the culprit. Call it willful denial. I replaced the sending unit with a brass fitting and an actual pressure gauge. Did the o-ring on the dizzy just last week. Driven probably 150 miles since last weekend... bone dry at oil pressure fitting and top of dizzy. 

I checked the receipts from the prior owner. The motor was rebuilt about 7 years before he installed it. Best guess, a bit of the seal was stuck to the crank when he turned it over it and it's just gotten progressively worse.

passenger side can be easier to disconnect because if the idler will not separate easily you can just pull the bolt & swing the idle out of the way as well .
If you have a rubber seal in there usually you can push one side up & grab the other end with small vice grips or needle nose & rotate the seal out without loosening the mains at all , just be careful sliding the new seal in as the sharp edge of the engine block can peel the back off the seal , seal kits used to supply a small nylon piece you can slide into the block as you slide the seal in protecting the outside edge of the seal .

Roger that.. thanks for the info!

[Scooter]

Compiling parts list for rear main replacement:

Actual rear main there are 2 listed by Fel-pro.. one rubber and one viton. Both for the 360 LA> Any preference? I know viton valve stem seals are preferred over the old rubber style.

1974 DODGE CHALLENGER Fel-Pro Rear Main Seals BS40094-Rubber
https://www.summitracing.com/parts/fel-bs40094/applications/year/1974/make/dodge/model/challenger?prefilter=1

1974 DODGE CHALLENGER Fel-Pro Rear Main Seals BS40651-Viton
https://www.summitracing.com/parts/fel-bs40651/applications/year/1974/make/dodge/model/challenger?prefilter=1


Oil pan gasket... they have a few listed for the 360 LA but all seem to be OEM cork with rubber ends.

1974 DODGE CHALLENGER Mahle Original Oil Pan Gaskets OS30520Z
https://www.summitracing.com/parts/mah-os30520z/year/1974/make/dodge/model/challenger

Could no locate an oil pump "gasket", just this o-ring:
1974 DODGE CHALLENGER Fel-Pro Oil Pump Gaskets 13338
https://www.summitracing.com/parts/fel-13338/applications/year/1974/make/dodge/model/challenger/engine-size/5-9l-360

Read around and there seems to be a pretty lively debate ala "tastes great vs. less filling"  as to whether or not to use a gasket. Sooo.. opinions?

Am I missing anything? Not planning on destroying the tie rod ends removing the drag link... but if I need to mashem to remove they are usually available locally.

[YellowThumper]

Cannot reply on seals as it has been forever.

Can say that the pan can be removed of the motor is lifted slightly. Raised mine with a 4x4, all thread and some chain.

[Chryco Psycho]

 The Viton seal should be the better one , don't cheap out you don't want to do this twice !!\
I would install a windage tray if there is not one in there now .
You absolutely need a oil pan gasket , there is no other way to seal a 1/4 gap between the pan & timing cover , , If you can find a 1 piece gasket use that it is a far better way to do it .
You will need a tube of oil resistant silicone to seal the corners .
Make sure the oil pump pick up is clean .
I loosen the nut on the tie rods & hit the center link where the rod end goes through hard with a hammer usually the tie rods will pop right out but you never know after 45 + years !!

[Scooter]

The Viton seal should be the better one , don't cheap out you don't want to do this twice !!\
I would install a windage tray if there is not one in there now .
You absolutely need a oil pan gasket , there is no other way to seal a 1/4 gap between the pan & timing cover , , If you can find a 1 piece gasket use that it is a far better way to do it .
You will need a tube of oil resistant silicone to seal the corners .
Make sure the oil pump pick up is clean .
I loosen the nut on the tie rods & hit the center link where the rod end goes through hard with a hammer usually the tie rods will pop right out but you never know after 45 + years !!

Heck.. I don't want to do it once...lol. Viton it is.


Anyone have opinion on the oil pump gasket?

[Chryco Psycho]

Oil pump gasket is not much more than a thin sheet of cardboard

[Scooter]

Oil pump gasket is not much more than a thin sheet of cardboard

It's barely that from what I can see... offered in copper as well 5ea. for $17:
SCHUMANNS DYNAMIC PERFORMANCE SSI60200 COPPER OILPUMP GASKET 5 PACK SB MOPAR 340
https://www.ebay.com/itm/Copper-Oil-Pump-Mounting-Gasket-5-Pack-Small-Block-Mopar-340/232617457162?_trkparms=aid%3D1110006%26algo%3DHOMESPLICE.SIM%26ao%3D1%26asc%3D20190920091355%26meid%3Da327c4569ed44a02a4cd9198a76abcfd%26pid%3D100036%26rk%3D1%26rkt%3D12%26mehot%3Dag%26sd%3D324179610855%26itm%3D232617457162%26pmt%3D0%26noa%3D1%26pg%3D2047675%26algv%3DDefaultOrganic&_trksid=p2047675.c100036.m2109

Million dollar question is are they even needed? Opinions seem split.

On the windage tray.. really any benefit on a low spinning motor? This thing is rarely going to see 5k rpm.

[MOPAR MITCH]

There has never been a factory-installed oil pump gasket on the small blocks.... it is metal-to-metal.  Gasket companies will sometimes offer it .. for usage IF the mating surfaces are not not perfect.  A anearobic sealer (cures in the absence of air) is preferred when sealing metal-to-metal.

[Scooter]

There has never been a factory-installed oil pump gasket on the small blocks.... it is metal-to-metal.  Gasket companies will sometimes offer it .. for usage IF the mating surfaces are not not perfect.  A anearobic sealer (cures in the absence of air) is preferred when sealing metal-to-metal.

Thanks Mitch!

[Chryco Psycho]

Windage tray yes there is a benefit 

[Scooter]

Well the mopar performance windage trays are backordered so we'll see if I can get one delivered before I go at the rear main.

Been doing some reading on the task... does anyone make a one piece oil pan gasket for the 360 LA?

Seems to be one for the Magnum.. reviewer says this will work on the 360 LA

Milodon One-Piece Oil Pan Gaskets 41007





Update.. Mildon site says for Magnum 360 only... gotta think they know their own product.

https://www.milodon.com/oil-system/pan-gaskets-lifter-baffle.php