58 original rear end?

[62lwbc10]

Hey guys my rear end needs some work (that sounded weird) and I'm wondering how to confirm if it is in fact the correct original rear for the truck. It's leaking like a sieve from the front housing where it mates to the rear itself (not from the rear cover). So what do u look for to confirm the rear is correct for the truck and not swapped out from a different vehicle? My truck is a 58 half ton step.

Thanks!
Mark

[Highsider]

Crawl under there with your phone and take a couple of photos.
Most guys here will tell you to get the production numbers off the top of the passenger side tube.
My fat head won't let me see them easily and what I can see doesn't help verify the year and type.

[Daze57]

yep picts will help ; you will prolly need to scrape off the dirt and crud to see the #s

[_Ogre]

pinion bearings going bad, wallowed out the seal causing the leak

[1project2many]

pinion bearings going bad, wallowed out the seal causing the leak

Could just be rust accumulated on the yoke and destroyed the old seal. 'Specially if it's still leather.

[Speedbumpauto]

If it has a rear cover, like he said, it's not the original diff. I believe all the 1/2 tons of the era had a drop out center section.

[1project2many]

If it has a rear cover, like he said, it's not the original diff. I believe all the 1/2 tons of the era had a drop out center section.

Original rear is C-clip with drop out center section. First page shows rear cover removed and C-clip removal process. Second page shows front of axle with removable pumpkin.

http://chevy.oldcarmanualproject.com...55ctsm0404.htm
http://chevy.oldcarmanualproject.com...55ctsm0406.htm

[Highsider]

In my '57 3105 panel. Needs a new gasket, eh?



Not likely original.

[1project2many]

Highsider,

No, not original. That's a "truck 12 bolt" used in many '70s and early '80s 1/2 ton pickups.

[Highsider]

Originally Posted by 1project2many

Highsider,

No, not original. That's a "truck 12 bolt" used in many '70s and early '80s 1/2 ton pickups.

Makes sense, but it seems "light" for the 1975 C20 I understood was the donor vehicle. What do you all think?
Couple of months ago I crawled under the rear end, cleaned off the top of the passenger tube, copied the numbers and lost the paper.
I'll try next week when I replace my worn out Flowmaster.

[59chev]

Originally Posted by 62lwbc10

Hey guys my rear end needs some work (that sounded weird) and I'm wondering how to confirm if it is in fact the correct original rear for the truck. It's leaking like a sieve from the front housing where it mates to the rear itself (not from the rear cover). So what do u look for to confirm the rear is correct for the truck and not swapped out from a different vehicle? My truck is a 58 half ton step.

Thanks!
Mark

When I still had the original rear in my 59 it was leaking from the pinion like you describe. I ended up getting a drivetrain shop to put in a new crush sleeve.

[1project2many]

Makes sense, but it seems "light" for the 1975 C20 I understood was the donor vehicle. What do you all think?

GM sells light duty 3/4 tons with semi-floating axles but they usually have 8 lug wheels. They used to sell a "Big 10" or "Heavy Half" pickup which could be had with a GVW just short of the 3/4 C20 truck's numbers (6200# vs #6400) and a theoretically higher payload capacity.

http://67-72chevytrucks.com/vboard/s...09&postcount=4

[Highsider]

Those are my tail lights!

[62lwbc10]

Hey guys trying to post some pics but not having luck right now . Pinion looks dry . It's leaking from where the nuts of the housing attach to the rear .

[62lwbc10]

Thanks 1project too many. According to the drawing in your link it's leaking from where the differential carrier mates to the axle housing . Is there a gasket there ? Since I'm going to be removing spindles etc. , what general maintenance should be done ? New seals? New bearings ? What else ? Not looking to rebuild at this time

[Rigmover]

To bad i.m not closer to you I have one out of a 58 gmc that's just sitting in my garage complete with 3:90 gears would bolt rite in.

[Rigmover]

Yeh! you have the original carrier style rear end 10 bolt rear plate and 10 nuts on the front half that holds the carrier in when new they had gaskets today we use silicone.

Best thing to do is pull the inspection plate of the rear unlock locking bolt and undo the C clips that hold axles in and pull axles change out the axle seals and pull the front carrier out change out the pinion seal and reseal the carrier to housing with silicone then your good to go that's about the easiest fix that you can do .

Rick

[62lwbc10]

Thanks Rick that makes sense so you think I should change the pinion seal too? It's not leaking at the moment. I also have a rear from a 55 that is ready to go. Do you think it would be better/easier to just switch rear ends or fix the current one?

[1project2many]

If that rear hasn't been used in a long time then it's a good idea to change the pinion seal. The original leather seals were fairly tough but they won't put up with any rust on the yoke. The '55 rear swap is probably more work although if you're unsure of how to change the pinion seal I can understand not wanting to try.