I'm trying to find some more information regarding the 1960 Eaton (HO32/33?) rear diff in my 1960 Suburban C10. It's 3.90 gears and I know it was built in 1960 so probably original to the truck. I picked her up several months ago and she wasn't running, but I'm about ready to fire up my newly rebuilt 350 with T350 trans. One of the last things to do was go through the rear diff. I drained the fluid, then cracked open the case to see what exactly I had. Everything looks good, EXCEPT one tooth on the ring gear has a chunk missing, but it's on the outside edge and a local shop told me to just dress it and due to location not worry about it. The pinion gear looks fine as do all of the other other gears. I did find a chunk of metal in the bottom of the pan and from what I've figured out it is one of the guide for the disc plates. I've tracked down part #'s but of course they don't seem to make much for this differential any longer. The local shop wasn't familiar enough with the axle to know what I was up against. I guess my question is how dire are these? I'm****uming without it's just a matter of time before the differential is toasted. Best estimate is I'm pushing around 330hp, if that makes much difference. I'm curious if anyone has had luck fabricating new guides and is that something, that someone with limited rear diff experience could tackle or is it a job for a shop? Last differential I messed with was 20yrs ago when I lost a ring or pinion gear in a 78 CJ5. I remember doing the work and she ran fine after, but I don't recall how detailed of task it was.
The eaton was a good carrier and I cannot imagine that you cannot find parts for it. if it were mine I would chase the pieces down and make it right.
My understanding is for the 1960-62, probably a few other years in there, they make very few parts. What they do seem to have is ring and pinion gears, but those seem limited to 3.43(?) gears. I have the 3.90, which might be horrid on the highway, but I'm not planning any highway use. I just want to cruise around town and turn the tires when the urge hits. I think I can also find the seals and bearings, but that's about it. With all that said, I did go this past weekend and grab a backup differential from a 1962, it is also a 3.90 gear, but it isn't posi. The guy that had it was planning on scrapping it, so he gave it to me for nothing, but my time getting there and back. Of course the posi should be more fun and would debatably add value, but I'm trying to decide if I run the current unit with the Posi, knowing those guides are missing and I can't get replacement carrier parts, or swap out for this one from the '62 while I hunt and see if I can rebuild mine correctly. Then the other thing, most seem to say, is find a newer one that has parts and build it.... Keep in mind at this point, it's not a total restore and have no plans for it to be a trailer queen. I just wanted something fun to cruise around town with the family.
The early truck posi is rare....really rare. I have a 59, but it's a*****er rear, not the Chevy design that you have. If you have a good guide to copy, then make your own. It's just a curved piece of steel with some tabs at the ends, right? And plan on replacing the whole rear end one of these years....
This is one of those times where that auction site we all know and love is your friend. Those older parts come up every now and then. Most guys would just swap to a more modern rear end, so the older parts don't normally sell too well. I am Butch/56sedandelivery.
I've tried Auction site, but have yet to come up with anything. I will keep looking though. I'm not really sure how many splines this is, haven't gotten that far with it. As for the casting number....if that's on the ring gear the number appears to be 3697702 GM 10 39 8 60 and stamped on the edge is B2. I know from that it is obviously GM, a 390 gearing and made in Aug of 1960. No clue what the first numbers mean or the B2.
3697702 is the part number of the ring gear, although the part number of the ring and pinion gear set is 3747808. totally useless info...but I happen to have the parts book, so there you go. and I learned something, the 1954 trucks used that same ring gear with a different pinion, than the 55-62 trucks.
'54 trucks were torque tube. A '62 head will fit a '48 housing but will be open drive. When I swapped my '55 1st series (open drive) head out for a '62 3.38:1, I noticed that the side gears were different. Splines were the same. Apparently later 12 bolt side gears are a straight fit which will allow the use of modified 12 bolt axles. I never new they made a posi for these, so this is interesting. I think these are the rears used in '57 Black Widows, and they had a posi option??
Here's what mine looks like. I think you can see the missing guide in one of these. If not I'll try to upload another image. I believe I have the part number, but I'll have to look later.
that guide is not like the ones I'm familiar with. Neat, it appears there is no spring preload on the plates? The 59 posi rear I have is like that, even though it's a*****er rear.
Real neat....sounds fun until you can't find parts! Tempting to put it for sale as collectors item.... Am I correct that I will need those guides on both sides? Also what does the spring preload do? Also, considering I have a spare axle, should I swap them out until I can find our make guides or just run the posi? My other question is how much work is involved in pulling the hub and installing the guides?
you might be able to just pull the bolt, the pin, and the spacer block, then maybe the axles, and then disassemble the posi while it's still in the housing. But I'm just guessing. Most limited slip rears have a spring to preload the clutches. This one appears to depend on the side force from the side gears. But I could be wrong.
Looks like a regular open drive to me. Are you sure it's a Posi? Undo the lock bolt, pull the pin, spider gears, and block. Then you can take the circlips off the axles and remove the side gears. There are thrust washers behind the side gears. The block can be turned to take up wear in the axles and side gears.
You can just about barely see a clutch in the third picture. That carrier is rounder and fuller where the clutches are. Weird. No springs. Those guides might be shorter that the later ones. Maybe still, you could cut one down and cut and dimple it to the right length.
There should be guides on clutches in third picture, correct? I ask because a parts list I saw only lists four, which might be correct I guess, by newer units, but I thought each side used 4 guides. I might have been thinking f incorrectly though.
No. Most later ones have two per side. I don't know what that other thing is. Twelve bolt truck , later model?? That thing will come apart with the ring gear in place. Almost sure of it. Let's see parts on the floor
Maybe I should clarify, I thought mine had four per side, as it appears to me each tab has two pieces. The parts guide only shows four total needed. As for parts on the floor. It'll take me a week or two to get there. I*****oned her up tonight, because I need to break in the engine and I'm hoping to do in next few days. I also need to run the rebuilt******* through the gears. Once that's done, I need to do my drop springs so maybe I'll swap axles at that point and tear into this one.
Now I'm really intrigued. Please post pics of the parts if/when you pull this apart. It's a rare piece.
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