C-Clip removal, pinion shaft lock bolt, crosspin, GM 10 Bolts (all)

Ok so this is a How-To. Ill show you how to pull the C-Clips, change the pinion shaft lock bolt, and crosspin. This is a very easy project, and you cant mess anything up, so dont feel nervous dealing with your rear end, theres nothing to it. This applies to all GM 10 Bolts, posi and open, both 7.5& 8.5 the later models are usually 7.6 & 8.6 but theyre all the same. So lets get started.

STUFF YOU NEED BEFORE YOU START: Cover gasket (i recommend felpro RDS55028-1 for the 8.5" carriers because it has holes to oil the axle shafts, you can learn more about that by clicking here), and new cover if necessary. C-Clips (you can reuse your old ones if they arent that bad). Lock Bolt Dorman #81048. And the crosspin. Im finding the cross pin is hard to find for stock applications so you can use the old one if you cant find a new one. And lastly, differential fluid. Manufacturer recommends 80w-90 gear oil, and if you have posi, an oil additive is needed if your using regular gear oil. You can buy GL5 fluid specifically for limited slip applications and you dont have to add an additive. On to the process.

STEP ONE: Remove the cover and drain the oil, my rear end is out of the car but yours will more than likely be in the car, so youll have to jack it up appropriately. Spin the differential until you see the lock bolt.


STEP TWO: Remove that bolt with a 5/16 socket. You may have to use a wrench if you cant fit a socket.


STEP THREE: Once that bolt is removed, you can proceed to remove the cross pin. If your only replacing the lock bolt then the following wont apply to you, you can stop at this step. On open differentials the crosspin will literally fall out, but on posi's the springs hold it in and you will have to hammer it out. What i did with my posi was hammer the pin out a little ways so you can still turn the diff without it hitting the housing, then i took the lock bolt that we just took out and put it through the hole on the cross pin, and then used a wrench and hammer to get it rest of the way out. Your replacing the bolt so dont worry about damaging it.


STEP FOUR: At this point you should have the cross pin out. If you have an open diff, becareful with the spider gears, you dont want them to fall out because they are a little difficult to get back in. On posi's you dont have to worry because of the spring assembly holds them all in place. With the cross pin out, you can now access the C-Clips. Pick any side axle to start with, push that axle you chose inward. You will now see the C-Clip in the housing, for the most part that too will literally fall out, but since my rear end is out of the car i had to fight with it a little bit. Usually you can use a small magnet to pull it out, but i had to use needle nose pliers. The C -Clips are easier to get out on the open diffs because the spring assembly isnt in the way, you may need a set of small hands handy lol.





STEP FIVE: With the C-Clips out, you can pull the axles out, theyll slide right out. At this point you can and should replace the wheel seals, bearing seals whatever you want to call them. If your just replacing the C-Clips you dont have to remove the axles.




It seems you made it this far, and this is as far as im taking you guys so from here it should be self explanatory to put it all back together, just follow the steps in reverse. This is really a fool proof project and its pretty cheap too. The lock bolt is $3, the C-Clips are like $4, the cross pin ranges i think $15-20, cover gasket is $6, wheel seals are $5, and then youll need a little over two quarts of your favorite gear oil, and additive if necessary.

All of the pics above are of a posi 8.5" carrier, you may have a 7.5" carrier and or no posi, which would look like this next pic.


Make sure you get the right cover gasket for your carrier. Alright guys i do believe that is it. If you have any questions please comment below, ill answer the best i can.

Wow, very detailed and informative!! I tell you, I can build and rebuild an engine from a bare block, do my own exhaust (when I have access to a welder), suspension, and even electrical, but when it comes to transmissions and axles, I'm "scared" to take them apart.lol I always have someone else rebuild them or I replace them entirely. Seeing this makes me want to give it a go on my rear end when I get it out. I may as well check it, especially that bolt before I put a nice coat of paint on it and bolt it all back in someday. I have no idea what rear end my '79 has. Does it being a 350 car mean anything specifically?

Theres a certain point to where id stop and have a pro do it, like a ring and pinion, those have to be shimmed perfectly. I also used to be scared of rear ends, and im not sure why i was and most other people are. But this How-To you can do at home without messing with any shimming or other major components. As far as your rear end goes, it just depends, mine came with a stock 350 and has an open 7.5 diff. But getting under the car you can physically tell the difference between a 7.5 and 8.5. The 8.5 is tons beefier looking than the puny 7.5. The 8.5 has a round cover, where the 7.5 has an oval cover, theres also little tabs under them to tell also, I actually found a chart to help out.


also heres my 7.5 rear end


and my 8.5 rear end

Excellent write up!

I'm a wuss when it comes to GM rear ends! The most I've ever done is a fluid change, and one time I fabbed-up a cooler with a little elect. pump to circulate the fluid.

For the cross pin do I tap in the new one with a wooden block or something

If you have a posi rear, its hard at first to get it in, i used a rubber mallet to hit it in, once its started its easy, pour gear oil on it first.

Thanks bro
Getting all my parts tomorrow(clips seals bolts and fluid) so getting everything in order for install.

Yo is the cross pin lock bolt rh thread or something
The 5/16 stripped it a lil on the first go and I using a new craftsman box wrench
Even the helicoil extractor socket isn't gettin it
Any ideas?

Those lock bolts have loctite on them, its hard to get it out man. I know

That what I was starting to think that's man now I know I'm not tripping

Damn this thing is kicking my a**
I tried every swivel joint I got a still can get it square to grab
Wedged a flat head from the inside of housing and against the ratchet head with a bat slipped over the handle and blocked the diff with a wooden hammer handle
They thing slightly stripped the extractor which sucks cause that thing has saved me before.
Any tips like heat on the bolt or something
Was gonna say f.. it and fill up with new fluid but I really wanna change the seals and other things

Yeah bro i know its a pita, but yeah try some heat, it was very hard for mine to come out, but i used a 6 point socket and it didnt strip it, did you use a 12 point at first? That little bolt sheared off on my old rear end and completely destroyed it. I hate that little bolt, that thing causes alot of problems.

Yea I used a 12pt that's probably why ..rookie move..
Well I try some heat but might need to fab a very short extension to get the head of the ratchet aligned with the head.

once you do get it out, take a pic if you can and put it up here, im curious to see how far yours has worn down

That's if I get it out ima try and tap it with a punch
I have a hex key that's thick enough to grab the head square but I don't have. My grinder to notch it to fit

Success ..taps with the punch and hammer on the top and side of the head(hit the edge of the bolt turning it counter clockwise) and the extractor got it out.
Will need a new socket but lifetime guarantee...all the teeth got wiped flat, still worked enough to get it out.
This job is very very easy just need to know how to approach it and this was my first time touching the inside of the rear end and had no rear end knowledge besides what's on this site's post.
-Drain Fluid
-spin diff to find lock bolt
-smack the top of the bolt head with a punch, then place punch on the edge that'll turn it counter clockwise. This breaks the blue loctite bond.
-place your 5/16" socket or 6pt box wrench*admin* and remove the bolt. Might be hard to get your ratchet to fit, lack of room
-push/tap with punch on the crosspin in a little then spin it and pull it out. Mine slid right out but if its stuck put the lock bolt and tap it out with a wrench.*admin*
-with the pin out you can pull the c clips. Push either axle in, the c clip will be visible. I used a skinny flathead with a magnet on the end. Push the clip to face down then pull with the magnet.
-with the clip out you can pull the axle shaft.
-the axle seals can be removed with a prybar on the inside flange of the seal. I did not have this and through a little trial and error found the AutoZone 2ton jack handle bar/favorite leverage bar worked great I cut the rubber away then placed the short bent end in the inside of the metal flange of the seal and alternating sides and putting firm controlled even pressure.
-lube the seal end with diff fluid and tap the seal evenly with a wooden block.
-slide your axles in
-place clips facing down so the seat all the way on the axle shaft and pull the axle outward to make sure the c clip locks and so the crosspin has room to slide thru
-Install your cross pin make sure you put the pin the with the hole on and facing the right way
-place blue locktite on threads of the lock bolt and tighten it up
-clean diff cover flange and place new gasket and cover
-fill with fluid and done

Thanks to the admin for this post and advice on the way.
lso thanks to rockauto for the parts (Yukon gear and axle) The lockbolt was a pain to remove till I used the punch and then figuring how to remove the seals. Everything else went smooth. If I had to do it again I'm sure I could do this in 30mins.

Awesome bro, glad to hear, minus that little bolt everything else is easy.

Yea I wasn't expecting that trouble it would have been faster had I used the punch from the beginning but seeing how easily the pin slid out I see why they put locktite
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