• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

383/automatic with rear main seal leak!

Russ Hood

Well-Known Member
Joined
Jul 23, 2020
Messages
395
Reaction score
403
Location
TN
Replace your PCV. It could be bad not letting the crankcase breath correctly and adding pressure to the crankcase causing leaks. I always try cheap and easy first.

Thanks
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
Well I got the 383 pan off and the leak in question was not the rear main seal, it was whoever did the pan an gaskets before and decided to make a RTV sandwich out of the gaskets,windage tray and pan and tighten way to tight. This makes me happy…next?
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
Got the pan gaskets changed and drove home a ways on a hot day here in the desert and found a half dollar size oil spot 15 min. later and a ready to drop oil drip on the weep hole of the flywheel inspection cover. Anybody think it might just be residual oil? Was told that everything back from the rear main was dry,so I went with it. If it is bad,can I get away with this add to the oil that seals up a leaking rear main or can it do more harm than good? Or just deal with the leakage until I can get at it the right way?
Thanks!!
 

Terry Hauck

Choadicus
Joined
Sep 6, 2017
Messages
335
Reaction score
295
Location
Mojave Desert
OIL LEAKS SUCK!!!
Did you take the inspection cover off to change the pan gaskets? Maybe it is just left over oil. Also did you change the rear main seal? If you did there is only one way that seal can go in. The raised lip goes toward the engine.
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
Inspection by my shop did not see anything wet from the pan back. They replaced the pan gasket and saw no evidence of the rear main seal leakage. But when I left the shop and drove home and shut down for 30min.
I found a quarter size oil spot under it.
The obvious is change the rear main seal and know it’s done or milk it along for awhile with the stop leak stuff which is temporary. Just concerned the stop leak stuff can do other harm…any thoughts?
 

Russ Hood

Well-Known Member
Joined
Jul 23, 2020
Messages
395
Reaction score
403
Location
TN
What if it does not leak when sitting for a while? I parked mine after driving. It leaked over night. I waited a week and then cleaned up the oil off the floor. A month later its not leaking. Thoughts?
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
Not sure on the sitting for awhile and not leaking. Doing my rear main seal (383) today and would like to let the pan gaskets with the RTV applied set up before running it. Mine did not leak only until I ran it and then if I wiped it clean and it sat a bit it was dry at next start up. I think a lot of other Mopar guys on here would agree…there are no guarantees with this awful rear main design,eventually it could leak again sooner than you would like.
Driving it is much better for the motor th as n letting it sit IMO!
 

V.R.D

Well-Known Member
Joined
Oct 27, 2020
Messages
475
Reaction score
562
Location
florida
if you have the rope seal a main sealer in a can can help all rope seals leak some .back in the day the dealers i worked for had paper or card board under so the floor was safe from slip and falls. clean the inspection cover removed and clean the bottom of the bell housing and wipe off then drive and watch for drip. if you get 5-10 i would leave it alone. i had the rubber have seal and it leaked 1/2 a quart in 40 miles and at 10 a quart it more the gas to drive. i just changed mine with the engine in the car and it took me 6 hr to perform this repair and i had a hoist.
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
I finally got the rear main seal done,went better than expected. Put in the best one of the three i had,came from Roseville Moparts in Michigan.Of course a fresh gasket set on the oil pan and we are dry for now and happy!!
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
Well the leak has returned after 50 miles. Can’t say it is the rear main,but when I inspect the pan bolts around the rear of the pan near the inspection cover they seemed quite loose and there was not any signs of rtv pushed outward in any of the gasket layers.
Pics might tell one of the experts the next course of action if any.
Thanks in advance!

72A2A892-DD70-4F09-B312-8C36250414FA.jpeg

06B0F603-E430-4F1D-BE7F-4A4A73DBDADC.jpeg

1C3CC00C-C5AF-4CFE-B216-223B3EA680AE.jpeg

9679DB57-557E-4D84-8FAC-83750ABF012A.jpeg
 

Russ Hood

Well-Known Member
Joined
Jul 23, 2020
Messages
395
Reaction score
403
Location
TN
Well the leak has returned after 50 miles. Can’t say it is the rear main,but when I inspect the pan bolts around the rear of the pan near the inspection cover they seemed quite loose and there was not any signs of rtv pushed outward in any of the gasket layers.
Pics might tell one of the experts the next course of action if any.
Thanks in advance!

View attachment 35792

View attachment 35793

View attachment 35794

View attachment 35795
Did you find out what the problem was?
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
Kind of a mixed report,had trans leaks at the band adjustment bolts and while fixing those discovered that it’s the pan gasket area over the rear main cap. I don’t think there may have been any rtv run in that area,but I’m going back in one last time making sure the shop does it right and No over torquing the pan bolts. Should just suck it up and put on jacks and do it myself. The shop warrented their work so I will hang with them while they do the job and learn.
Is permatex aircraft gasket seal any good for these big block pans?
Thanks!!
 

Terry Hauck

Choadicus
Joined
Sep 6, 2017
Messages
335
Reaction score
295
Location
Mojave Desert
I don't see oil. I do see what looks like antifreeze. Could be a head gasket or a freeze plug. Hard to tell by a picture.
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
The shop did mention a questionable freeze plug. Don’t have antifreeze in the oil. The wetness in the pan gasket indicates to me that the gasket layering with the rtv was not done right. I know these old motors are going to eventually develop leaks but not after the leaks addressed have 50 miles on them. Another good reason to suck it up and jack stands and other safety things and crawl under it and then I’m sure it’s done right! I would like to have it all exceed my expectations,but let’s be real!
I’ll get there! Thanks
 

woodwiz

Well-Known Member
Joined
Dec 10, 2020
Messages
501
Reaction score
374
Location
Tucson,Az.
That green is old paint,I have rubbed on it and it is not wet nor does it rub off.
 
Back
Top