55.2-59 1955 6400 Differential Seal. PLEASE help me.

[Keekstech Performanc]

Hey guys, I have a 1955 6400 and I am having troubles deciphering which seal i need for the input/pinion gear I have a leak thats finally bad enough where it has to be fixed.

The only stamps I can find on the differential are as follows:
3711470 - gm
and
CH712

If anyone can direct me to the proper seal id be so grateful. If i call any parts stores they ask for the manufacture and model of the differential and im so lost. Thanks again!

[mr48chev]

Well you need a real old school parts person at a real parts house but those are few and far between now.

The other option is a bearing house Like Kaman industrial, Bearings Inc or what ever is in you area.
Take a micrometer or caliper and measure the shaft that the seal rides on. Better yet If it is the pinion Clean it up and take it with you then they can easily measure it. . Take the old seal and do the "can you get me one to replace this?" thing.

It looks like you have Applied industrial Technologies there and Canadian Bearing just across the border Plus probably a few more.

[Keekstech Performanc]

Hey thanks for the reply it certainly looks like my only option is to do as you say take to old seal out and try and copy it. Was just trying to avoid having it off the road for spring but I guess ill keep dreaming!

[dsraven]

drain the diff (it's probably due anyway), pull the pinion yoke (if it's tight get a puller, no hammer. it makes divets in the bearings), then carefully pull the seal with a seal remover trying not to damage the steel body of the seal. sometimes screwing a sheet metal screw into the seal and using some vice grips and a pry device will work. check the pinion yoke for wear where the seal lips ride (use a caliper, eyeball is not good enough). there is probably a speedi sleeve available (google if not sure what that is) if the pinion yoke is worn too badly. if it is too far gone then check into a new part or have the old one spray welded and machined down to the proper diameter. take the whole shooting match to a bearing and seal place, like Canadian bearing, applied industrial technologies, ontario bearings and industrial supplies etc. google it for something closeby. they will measure the pinion yoke for the inside diameter required and the outside of the old seal for the outside diameter required. then they look it up online or (if you get the old guy) in an actual parts book.
when installing try to use a tool that fits the seal properly so the seal lives through the process. drive the seal in with a tool that fits the steel part of the seal and not the rubber part. sometimes a big socket will fit, a piece of plumbing pipe, a pipe fitting, whatever. just ensure the piece is long enough to drive the seal all the way in and square with the housing. I use a bit of aviation form a gasket on the outside of the seal but some seals come with a sealer on the outside. lube the lips of the seal prior to install because it is easier (some come prelubed so check first) then use some quality silicone sealer inside the yoke, on the splines, so gear oil stays in the diff and doesn't creep down the pinion shaft. not much required so don't over do it. slide the yoke back on and use a new nut to keep it there. sometimes a bit of help is required with a dead blow hammer to get the yoke on far enough to fit the nut on the threads and be able to pull the yoke onto the pinion. again, don't over do the hammering because it isn't awesome for the pinion bearings. torque to spec and you're done that part. use a pipe wrench or another tool to hold the pinion yoke while you torque t up. don't forget to fill the diff with gear oil after.

[mr48chev]

The whole process shouldn't take more time than what it takes to get a new seal shipped in to the bearing store if they don't have one on the shelf.

A couple of hours to take it out and a couple hours to put it back together if you don't get in a hurry.

[Russell Ashley]

Most of the seals I've ever seen have a manufacturers symbol and a number on them stamped into the metal ring. I would remove it and see if you can find any identifying information on it. If you do you will probably be able to cross reference it to a new number.