Help me find the hole?

[Guest rotten03]

I'm getting ALOT of rear end noise in my 50 Plymouth. I mean so loud that you can't have a conversation in the vehicle. I'm not sure what is going on with it. The ring and pinion out of whack or what. The first thing I want to check is the fluid level. Only problem is I can't find the fill plug. On the bottom there is a plug, that I am assuming is the drain plug based on the fact it is on the bottom. UNLESS the guy put the rear in upside down. But that seems like a stretch. Any idea of where I would find a hole so I can pour in some gear oil? Does anyone have a diagnosis for the noise? I'm getting a lot of advice telling me to swap the rear for a late 70's mopar. Seems to me that a new rear would be cheaper than having a new ring and pinion put in. I'm terrified to tackle anything inside a punkin. Too much can go wrong.

[Guest rotten03]

Thanks for the pic. I've been all over this rear and there is nothing. It's driving me nuts. I just went and checked again based on your pic. Nothing like that. Drain plug looks the same but no fill.

[50PlymouthSled]

I have a 50 Plymouth too, Rotten, I'll have a look and see what I can see. If I find it, I'll take a picture and show you.

[Guest rotten03]

I have a 50 Plymouth too, Rotten, I'll have a look and see what I can see. If I find it, I'll take a picture and show you.

I hope you can find something. I'm starting to think i'm crazy. Its like a needle in a haystack. It shouldn't be this hard.

[Dodgeb4ya]

I think your "pumpkin" has been swapped out at one time.1941-48 Chrysler /DeSoto rear ends are filled through the back of the axle housing, unlike 1949 and later MoPars which are filled through the diff case plug.Therefore the filler plug is not in the differential case!

Bob

[Guest rotten03]

So I wonder how the old owner got fluid into it?

edit: I guess they filled it before they put it in. I guess that's what i'll do. Unbolt the damn thing, flip it over and pour a bottle of fluid in. Wonder how much is enough.

[Dodgeb4ya]

I`d pull the drain plug and see what comes out (silvery goo)-ring and pinion /bearings worn out.If not much comes out-where did it leak from? Does the pinion seal leak/gasket leak?. Put the plug back in and a quick way to filler up would be to remove the vent bolt that holds the brake line junction block to the top of the axle housing. It`s not too big of a hole but W/ a new bottle of 85/90 and a new small bottle tip it will work. I think 3-1/4 pints would filler up.

Bob

Bob

[FMSPEED49]

My '49 dodge is identical to the first photo.

On a side note, I have never in 20 + years in the automotive field, seen a rear end that did not have a fill hole somwhere, I have seen chevrolet rear ends where the only way to DRAIN the is to pull the inspection cover.

I would almost bet, someone put a recessed plug in the fill hole, and it is now packed with road grime so bad you cannot see it.

[Jerry Roberts]

When swiching parts on a mopar rear end I ended up with 2 fill holes and 1 drain hole . So I can see how someone might end up with no fill holes . P .S . My 2 fill holes were at slightly different levels .

[Normspeed]

Well there you go. Jerry, you got his fill hole. Give it back.

I like dodgeb4ya's idea, drain it, take a good look at what comes out, and refill to a specified amount through the vent hole. It would take a while to fill that way, but if it there are no leaks you'll know you have the right amount of fresh stuff in there, no worries.

[Dodgeb4ya]

You could use a hot wrench and cut a hole in the housing and take a quick lookie then filler up and punch a cork in the carefully burned access hole!

Well maybe not!

Bob

[Guest rotten03]

I can say 100% there is no fill plug. I've been all over that rear end with a screw driver, poking at every place I could. I guess that they combined two rears. That's the only thing that makes any sense. I like the idea to fill through the vent hole. I honestly had no idea there was a vent there. I see the junction for the brakes. There is a nut on top of it. If I loosen it up with a wrench it will come off and let me at the vent? Then I guess I could use a brake bleeder or something to add fluid in. That's a hell of a lot better idea than me flipping the whole rear end upside down. What a PITA. I would like to swap out the rear end but then it all starts snowballing, well since the rear is out I might as well 4 link it etc.

Dodgeb4ya: I got a new plasma cutter. Believe me I was tempted to pull it out.

[Dodgeb4ya]

Just pull the vent bolt and use the gear oil plastic bottle pointed tip and squirt it in. I think the vent bolt thread is a 3/8X24 thread. Plenty big to filler up!

Bob

[Normspeed]

I'll bet your arms are gonna get tired up there:D

[Brendan D25]

Good chance somebody changed the center section, a friend of mine has a 69 Mercury Montego with the same problem. If there is not enough oil in there the differential would get noisy. If you put in too much you could end up with oil seal problems. Also if it is low on oil the center section will be hot after a long run.

[Guest rotten03]

This may sound like a stupid question. Someone mentioned that you need a 5/16 square drive to get the drain plug out. What is that and where can I find one? haha this whole thing has gotten ridiculous. I just want to put fluid in the rear!!!

[Young Ed]

Try a ratchet extension in the plug. Sometimes they are the proper size. Otherwise you need a socket that would mimic that in the proper size for your plug.

[PatS....]

How about a little pump up garden sprayer for filling. Pour the correct amount in, pump up and fill.

[FMSPEED49]

I ground down a allen wrench to fit, and painted it red and leave it in the truck, a sacrafice to the mopar gods if you will.

[BobT-47P15]

Mine just has this plug on the back side.....pretty obvious. It is a plug,

not a recessed hole. Only need a wrench.

[Ed Griffin]

Hope you find a plug before any damage is done. Rode a 84 Harley down to Hattisburg, MS. and made an even swap for a 76 GMC Sprint that was supposed to have been checked over. About 60 miles up the Hwy heard what sounded like ujoints going bad very quickly until then a huge thump and lots of clatter in the rear. Turned out the pumpkin was bone dry and ended up having a junkyard rearend installed just to get home. One of the axles was so badly seized the biggest guy on the crew couldnt get it loose to swap out. It stills sits in the back yard as a reminder.

[Guest rotten03]

Digging up an old post. Thought maybe some of you were losing sleep at night since I couldn't find the fill plug. I took my truck into Oil Can Henry's for an oil change. Started BS'ing with the guy in the pit about my Plymouth. Telling him how I cant find a plug. Long story short I bet him a 6 pack he couldnt find it. Brought in the Plymouth. He couldnt find a real fill plug but he found a plug at each end of the axle housing near the drums about 1/4 of the way up. Don't know what the hell those plugs were but we found out there is gear oil in there. SOOO looks like a new rear is in order. I'm not 100% sure what rear is in this thing now. Some swear it's a Ford 9" others it's a stocker, others say its a Dana. Me I dunno. All I know is I'm junkyard hunting for a late model rear with roughly the same dimensions. Maybe an S10. Cant seem to track down a Dakota rear. Then I tracked down a metal fab guy. Since I'm gonna have the rear out anyway. Might as well have it 4 linked and a new bridge notch put in. I can't wait to see what the bill for that will be.

[Tom Skinner]

Well there were 2 different rear ends in 1946, 1947, and 1948.

The one with the plug on the rear hump of the Pumpkin was a C-38.

The one with the 5/16" Drain plug at the bottom of the pumpkin a C-37.

Chrysler, Plymouth Dodge and Desoto installed whatever they had in stock

at the time of assembly.

The 2 plugs you removed on either end of the axle that bled gear oil

only prove your inner rear oil seals are shot, not that you have a fubared rear end.

I would try to eliminate the possibilities before I would let some ignorant

mechanic bill you for ignorant work.

Tom

[greg g]

those [lugs at the end of the axle are to allow you to push in a bit of wheel bearing grease. They should not be replaced with zerks as a gun will over pressure the seals. I believe the manual says to work some in with your thumb while turning the wheel to spin the axle.

[Guest rotten03]

Hmmm. So I still have not found a way to get gear oil in the pumpkin. Damn. I tell you i'm ready to replace the rear end just so I can put fluid in it.

How about drilling and tapping a hole in the rear of the pumpkin and putting in an oil plug? Bad idea?