Rear Main Seal

[noreastfish]

Can anybody share any tricks for replacing the rear main seal. Do you have to lift the motor to clear the oil pan?  Do you have to remove the trans ? Somebody told me to use a sneakyPete tool. Has anybody used this tool and how does it work. Any help would be greatly appreciated.

[Stacked440]

You need to pull the trans, usually they include a plastic line up tool with a new rear main seal, I try to find a piece of pipe that fits around the outside of the seal and pound it in with a dead-blow mallet, helps so you don't distort the seal or break it while putting it in.  Mine looks to be leaking as well...but I ran the motor for maybe...2 mins.  So I want to run it really well and then check it...NOT A FUN JOB with the motor in the car   I've never heard of a sneakypete...   Best I can tell yah.  OH, and PRE-LUBE the seal with oil before you put it in

[matt63]

I haven't had to remove the transmission to remove a rear main seal.  I think that Stacked440 is talking about a grease seal.  The oil pan can be removed but you will likely have to split a few ball joints so you can drop the crosslink.  A sneaky pete tool might help if you still have the rope type rear seal otherwise you won't need it.  All new rear seals are split and you should stagger the splits so they don't match up with the split line of the block/seal cap.  They are also very easy to put in backwards.  What engine and transmission do you have?

[Chryco Psycho]

  with Matt
 the seal can be changed without removing the trans , you can sneak the oilpan out with the engine in place & the cemter steering link diconnected & swung out of the way

[Robb]

I gotta do this pretty soon myself, but Ill have the motor out of the car.


To change both halves of the seal, do you have to loosen the Crankshaft main bearing caps at all,  to get clearance from the crank to get the upper seal in and out ?  or can you just feed it on through there, and if so, with what ?

 is milling .010 off the Rear Main Seal lower cap advisable still, too ?

Thanks,  Robb

[Chryco Psycho]

the rubber seals will generally push around the crank without dropping the whole crank down , the rope type may need the crank dropped to get the upper 1/2 out

[noreastfish]

The motor is a 383 with an automatic trans.  Iwas told that you would only have to loosen the rear main cap bolts.  Do you think I should loosen all of the main caps to get a little more clearance? 

[matt63]

You have to remove the cap that holds in the rear main seal.  You might get lucky and not have to drop the crank to pull the old seal out.  If not, you will have to loosen all of the main caps.  This means loosening the belts and possibly undoing the flexplate.

[Stacked440]

???Dunno how Chrysler does it, I've only done one on an International Scout II

[ViperMan]

Hmm, I was told repeatedly that you have to drop the transmission...  My 318 is leaking, too.

[quagmire]

You only have to pull the trans to replace 1 piece rear main seals, which are generally found on all cars and trucks from about the mid 80's onward.  I've done numerous 2 piece seals on cars, including several chrysler small blocks.  Usually you just need to loosen the main caps, there should be enough slack for the crank to drop without loosening belts or disconnecting the torque converter.  I'm not positive, but I thought the big blocks have a separate adapter that holds the seal in, instead of using the rear most main cap.  You might not even need to loosen the mains if it isnt stuck in there too hard.  They have special tools for rope seals, but I think most replacement seals are .  I usually use a small screwdriver wrapped in electrical tape to push the upper seal half out.  Be careful not to scratch the crank or the cap sealing areas.  Then you use a little RTV to seal the cap, making sure not to get it on the seal part that contacts the crank. 

[Challenger6pak]

This might help.

[Alaskan_TA]

This may help as well;

http://www.hamtramck-historical.com/images/TSBs/1970/1891%20page_1.jpg

http://www.hamtramck-historical.com/images/TSBs/1970/1891%20page_2.jpg

[matt63]

I've changed a big block seal without dropping the crank.

[rottenfish]

Late to the party on this one...  In my case it was easy to change, didn't have to drop transmission or touch any of the mains. The B/RB seal is in it's own retainer, as opposed to the small block setup where it is integrated into the rear main cap. I have *never* had to touch any main caps to do a rear main (other than the rear main cap on the small blocks, obviously), but maybe I have been lucky. It can be a bit tough to get the old rope seals out sometimes, but with a bit of patience, they will come.
You will probably need a 3/8" 16 point socket to remove the retainer, if I recall.
Here is a pic of the setup on my 440.
http://www.wlrgroupco.com/auto/ramcharger_page_2.htm