monzaz

Hi guys, I am new to your forum. I do not have an oldsmobile... I do however build GM Muscle Car rear differentials at J D Race and Restoration in Richfield,Oh. I have been answer questions on the driveline section of your forum for a cuople of weeks. I am not a spammer ...lol. I Just wanted to let you all know that I am just here to try to help iron out any questions you might have on GM rear differentials and others too if needed. I am not here to insult anyone and will take every question seriously, even questions considered common knowledge to most people on this site. I have had many A-body 1965-1972 GM cars over the years and still have my one plus other f-body and h body cars. I am GM through and through. I can tell you I know my 1965-1972 GM Diffs inside and out plus others. No one knows everything and I am always humble enough to learn what might be new to me also. If I do not know the answer - I will not make something up... I will either find the answer or plain and straight tell you I DO NOT KNOW.
I hope this helps understand who I am and why I am answering your questions. If you all deside I do not belong then just let your head Olds man know and he will do what is necessary to clean up the site.

I am a helping hand in the confusing world of diffs. I care and can help you find some hard to find differential gears and parts also. Good luck on all your restorations and part hounding. Thanks, Jim Mitschke

Oldsguy

Jim, welcome to our site, good to see some experience in the world of differentials here.

88 coupe

I suggest you limit your, self serving, replies to current threads, rather than spamming dead ones to the top.

https://classicoldsmobile.com/forums...nd-ratios.html

On a a board such as this one, it is generally assumed that a message at the top of a forum is current. It is for this reason, posters whose primary mission is help, rather than self promotion, do not bother to check the date of the original post before responding.

Yes, spam is the applicable term.

Norm

monzaz

I will try very hard to look at the dates first before answering. I was at first just looking at subject matter not dates. Jim

88 coupe

I'm sure, I'm not the only one who thanks you.

Norm

dynamic88

jim, i have a question for you. i have a 65 olds dynamic 88 convertable with 425 motor. i recently replaced the rear pinion seal on the rear end because it was leaking. the seal was hard to come by for this car. i dont know if the rear end in these were special or what but the local parts stores did not have a seal for it. i did find one and replaced it. the one i tool out had a small lip around it that seated up against the outer housing of the pinion. the new seal did not have that lip but was the same size in dia. the new one was an actual gm seal for it. a guy told me to put it in the freezer so it would contract making it easier to put in and when it warmed up it would expand. so thats what i did. before i put it in a smeared a little grease around it to make it easier to put in. so after it was in and all said and done and the new seal was in. i ran it up and down the driveway and put it away. couple days later i noticed its leaking again. any ideas did i do something wrong? thanks chris

Olds64

Hey Dynamic88, I don't know much about rearends but you might want to try to retighten those bolts. Maybe they are just loose since you just put the cover on.

Now I will make myself look stupid. Jim, could you give me a quick rundown on the different types of rearends GM used in Oldsmobiles from the 50s to the 70s. I have heared people refer to the type O rearends. What is a type O rearend? I know what 10 bolt and 12 bolt rearends are. Are the Olds rearends different from Chevy rearends? Or if you have a link to a good website that would work too. I just don't know much and I want to learn.

dynamic88

its not the pan on the back if thats what you are thinking olds64. its the seal on the front of the differential where the yoke goes. if that makes since. thanks chris

Olds64

Ah, I see. Like I said, I don't know much about rear ends.

dynamic88

that makes two of us. lol

monzaz

It's ok guys...lol. Will figure it out. Now I do not want to get in trouble for starting a rearend discussion in the general disscussion area. Is this ok here or should we move it to the drivetrain section?

You should never have to put a seal in the freezer to shrink it and it should have come back to original size ... anyway it needs to be pressfit and should not be that difficult to do.

The prep work is critical, all oil should be removed from the housings sealing surface...wipe it with lacquer thinner on a rag or brake cleaner in a rag.

What I do is use black silicone sealer on the outer parimeter of the seals press in surface...what this does is help take up any imperfections, nicks etc. from removal of the old seal. (STUFF HAPPENS I know...lol) Do NOT put it on the housing first or it will get push into the bearing area...NOT what we want.

SO now the hard part, how to get the seal in with a pinion shaft sticking out in the way. Well you could tap criss cross around until it is in flush with the edge of the casting. Do not recess the seal! You can use a big 3/4" socket set if you know a friend that might lend you the right size socket and extention...you must have patients to get that first initial seating of the seal in square. It is alittle tricky but everyone here that can turn a wrench should not have any trouble .

Another thing that could have happened ...maybe you lost the spring from behind the seal lip upon install and it is just laying in there behind the seal not keeping tention on the seal... check your next seal see if it has one if not then another reason might be - you just bent the seal metal enough to make the seal center out of round .

My suggestion is to find out exactly where it is leaking from on the seal. The rubber or the press in fit between the housing and the seal outer parimeter. Jim

If it is the outer parimeter then you know you need the sealant next time. If it is the seal around the yoke ...??? something when wrong with the install OR you just do not have theright seal...Maybe? It is hard to tell unless I am there. Do you have the part number or receipt.? Jim

monzaz

Could you please post this question in the driveline forum and I will be glad to run down what I know about olds rears and shoot some different site to check out. Ok? Jim

dynamic88

Jim, thanks for the reply. I did not do any of the prep work you described. I just put the seal back in. I will have to take it back apart to see where it is leaking at. It sounds like it was a good thing I picked up a spare seal off ebay. These things seem hard to come by for this car. Its a gm #9778370 if maybe you have a source for them I could check for more. Is there an easier way to get the seal out without damaging it or the housing besides a screwdriver and hammer? thanks chris