The Stovebolt Site Forums The Shop Area Driveline Differential

In looking for suggestions for a diff I can pick up at a reasonable price for a '53 100. It's got a diff from a 1970 C10, from what I gather.
The bolt that keeps the pin inside the spider gears was broken so I had to pound out the pin. All the seals are shot, the bearing on the rh side went out and there were roller pins all over and a groove in the shaft... The previous owner should be banned from owning tools.

The conditions which you describe for your differential are signs of a typical high-mileage unit in my experience. They don't last forever and they are a challenge to work on for most people.
If we ban that guy from owning tools, then I will then need to turn mine in.
Sorry about your bad luck on that one.
Take a tape measure to the junk yard or Pick-n-Pull and find a six lug axle close to the same width as what you have. Pull the cover to check the condition.
Carl

You're right. The seals are wear and tear, but this guy snapped the cross shaft pin, installed an incorrect hub which damaged that spindle, packed the entire inside of the hub with grease, installed the rear rotors on the front which damaged the tie rod... Dude has no idea what he was doing. I just wish I would've seen it before making the purchase.

OK, were does he live? Does he have any good tools?

I located a '95 Yukon 12 bolt with 3.42 gears and some form of locker/lsd. Waiting to hear on the width. Mine is approximately 57.5 from backing plate to backing plate. The guy is asking for $550 obo... Thoughts?

That Yukon rear is going be too wide, and I question the listing if they have it listed as a "12 bolt", as they never used 12 bolts in the Yukon. The Yukons, and pretty much all 1/2 ton GM trucks after '77 have 10 bolt rears.
On the mention of the broken pin bolt, that's actually a very common problem. I've seen them broken from the factory.

there always rants on this forum and others,about po&and there bad mechical abilti(also bad spelling).just once I would like to see the terrible po speak up..have you approached this person?by the way what did you pay for this bunch of junk?would you be that quick to share that with us.?

I double checked the post and you're right. It does not day it is a 12 bolt. He measured it at 59.5..

I paid $1700 because the engine looks to be in decent shape and the body is pretty straight. What do you recommend I call him and say? " Your mechanical skills suck"? Or perhaps "Great job hiding all the problems the truck had to secure the sale"? I'm all ears...

He has a good 9in open diff that matches my current width (57.5). What would be involved in making such a swap?

Weld-on spring perches. Classicparts.com

That sounds very do-able. Since I'm going to have to do a little welding on the cab corners, I might as well pick up a little welder now. I'll also have to see what gears are in it since the owner does not know. Before committing, I'm going to check a few junkyards and see what it would cost me to pick up a differential case, an axle shaft, and a seal kit.
Does the frame taper out from behind the cab to the end of the bed? My measurements from perch to perch was 40 in., but that number gradually grew as I measured the distance between the leaf springs moving towards the back of the truck.
Also, do I need to do anything as far as the u-joint goes? The drive shaft seems to have been modified as it looks stock at the front but is not a torque tube setup. It has a regular drive shaft that connected to the 12 bolt.

Has anyone installed a Colorado/Canyon diff? I'm thinking it won't be too wide, will be readily available, and has the 6x5.5 bolt pattern.

gusco
I drive a 2 wd Colorado as my work truck.
Let me know if you need dimensions on the rear end.
delky dave

I'd greatly appreciate it! I'm looking for the width from backing plate to backing plate. Everything else will probably have to be stripped off and new perches welded on.

It might be better to take your measurements from the wheel mounting surfaces. Some rear ends have wider or narrower brake drums/rotors, which will alter where the backing plate will be located.
Carl

Sounds like great advice, but my axles are off and I can't quite get that measurement. I'm hoping to just be in the ballpark of what I have now. Perhaps even a little less since the back measured in about 5 in wider than the front even without the rotors on the back (another 4 in)

9" diffs didn't come w/ 6 lugs. A late 3/4 14 bolt SF might be the right width.

$150. Might be a decent price around here.

gusco
I finally crawled under the Colorado, I'm old & got bad knees, but I got under there and find that inside of brake backing plates is about 56" to 56 1/2"----not too scientific a measurement as it was late evening and I was all alone under there ---- knees were sore anyway, from tilling the garden most of the afternoon.
Hope this helps---note that mine is a 2wd. Most are 4wd and dimensions may differ.
delky

Thanks for the effort and the numbers. I tried seeing if I could find anything at all the local junk yards, but I had no success. They can't pull up much info and don't have very much stock from 70s cars/trucks. A guy offered me a 2009 Canyon diff with 3.73s dor $250. I told him I'd take it only to find out it was already sold. I found one case on ebay, but the GM part number is different from mine (mine:3866116 ebay:30060). Does anyone know if that case will fit? The Colorado diff seems very close in total width and the perch locations (approx. 40"). Is there another diff I could be looking into? S10?

What do you mean by SF?

SF stands for Semi Float. GM has 2 different 14 bolt rearends, the 10.5" ring gear full float, and the 9.5" semi float. The full float axle only comes in 8 lug, but the semi float version was made in both 6 and 8 lug. '88-'94 light duty 3/4 tons have the 6 lug version, as do '92-'98 1/2 ton trucks with the Z71 off road package, usually with the Sportside bed option. That axle will be too wide, especially if it came from a 4x4.
You mention looking into an S10 axle, those will be 5 lug, and will be a bit too narrow unless you get the 4x4 version, preferably from one with the ZR2 Wide Stance option.

Thanks, Longbox! The more I think about it, the more I think this snapped bolt is going to cost me an entire diff replacement. I can get a Colorado diff for $400. I may have found a carrier on ebay for $150+$20 shipping+$135 for seals and installation kit+$120 for an axle=$425.
Does anyone have the total width of an original axle, measuring from the wheel mounting surfaces? I don't have a bed on now and I don't want to take a route that will make more work for me later.

In still hoping to hear the total length of the original from anyone. I'd appreciate any help.
It got tired of waiting to sort the diff problem and got working on firing up the engine. It started, but the transmission seems to be stuck in gear. When I put the clutch in the driveshaft stops turni
ng, but when the clutch is out (even though I think it's in neutral) the driveshaft spins. Ideas?

Well, a little patience paid off. I scored an Eaton posi unit of eBay. Now I just have to see if the damaged axle is good enough to be run or how I can repair it and fresh seals, bearings, and take a crack at reassembling... Which by the looks of it is not going to be easy.

With the engine off and the trans in neutral, turn the output shaft by hand, if it turns it is in neutral. Without the drive shaft connected the oil inside the transmission and the drag on the bearings, the output shaft will turn with the engine running.

Figured it out. Thanks though.
Now I just have to figure out if one of these axles needs to be replaced and how I'm going to get that crush sleeve on...

Hi try partsonline.com for 1968-1972 chevy C20 diff/carrier

I picked one up of eBay. I pulled and washed out the diff today (lots of rust shavings in the tube from a missing rh seal. I need to decide what to do about the grooved shaft (rh). I'm tempted to just get both axles new and maybe re-gear to 3.73 (it's a 4 series carrier).

I ordered a rebuild kit from Summit (Ratech) that is supposed to have all the necessary seals, bearings, and shims to get this thing done. I also got a new axle shaft. I've never set up a diff, but I've been watching a few youtube videos and hope it goes well.

Everyone needs to set up one differential so that you will know to never do it again. And besides, there is a place on the Man Card which gets punched for accomplishing it.
Carl

Parts are in; the kit looks good: Timken and Koyo bearings. I'll be working in it Monday and hope everything goes well.

When you get done, make sure that you look down your nose upon the commoners too scared to attempt it. For a while anyway, as it will soon become annoying to some.

Until about 8 years ago, the only mechanical parts that I had not touched on any vehicle was the differential and a transmission.

The first rebuilt and upgraded differential has been working fine since then (1954 torque-tube 3.55 R&P and new bearings/bushings/ seals). I did this with a knowledgeable and talented friend (who was awed by the torque-tube) - smooth, quiet, fuel-efficient operation.

I had my 1954 Hydra-Matc transmission rebuilt by am eccentric professional. I'll probably have my 3-speed also rebuilt by a pro.

I got the easy part done today! Races are installed and the pinion and diff housing are at the mechanic getting their bearings pressed on.
I still have to decide if to paint it or leave it rusty to match the rest of the truck...

Oh, and the outer bearings.

Hey Gusco

When you get it all done can you share wit us how it actually went...I gotta 1985 K5 Blazer (6 lug) 10 bolt for free so I stuck it under my Howard Knapp truck...I found out the gears in my rear end was a 4.10 and I would love to get that number down to 3.42 so I actually can drive this on the interstate....4.10 will be good to haul stuff but actually being able to go with current day traffic flow 3.42 would be much more enjoyable.

Also how much did the kit cost from Summit?

MikeC

I plan on updating this thread with every bit of info. I find that is more useful than starting several threads.
The kit was about $100.

Update: Got the diff case back from the mechanic with the new bearings pressed on. I also had a little while to get started on the pinion. It was a little tricky to get the outer bearing to start moving in on the shaft. The nut kept catching on the splines, but the washer was too thick to allow for it to be used initially. I'm going to try to set the preload and maybe get the case and shims in as well.

Update: I got the crush sleeve started, but did not finish torquing it down. When you read that they are tough to get started, they are not kidding. It took me (200lbs.) standing on the end of a 18in or so breaker bar to get the free play out between the pinion bearings.
I am waiting for a in-lb dial torque wrench to come in that I purchased on ebay so I can make sure I have the right amount of preload on there. I also measured and labeled all the shims to make quicker work of setting up the carrier. I still need a dial indicator to get the backlash right.