Rear axle replacement

[Pmcb]

I was driving down the road when I heard a thump in the rear end, slowed and pulled to the side but at about 35mph drivers side rear wheel and axle shaft passed me. I was able to keep truck under control and get to the side of the road. Axle shaft pulled out of both sides. I do not see other damage, drive shaft and suspension look good. It is 1987 GMC Sierra Classi, V1500 with 5.7l.

How do I find out what the ratio is for replacement?
Should I replace enter rear axle or rebuild?

I have never worked on axle before.

 

[dhartman]

I was driving down the road when I heard a thump in the rear end, slowed and pulled to the side but at about 35mph drivers side rear wheel and axle shaft passed me. I was able to keep truck under control and get to the side of the road. Axle shaft pulled out of both sides. I do not see other damage, drive shaft and suspension look good. It is 1987 GMC Sierra Classi, V1500 with 5.7l.

How do I find out what the ratio is for replacement?
Should I replace enter rear axle or rebuild?

I have never worked on axle before.

Glad to hear that you are okay... that could have been so much worse.

Very curious as to how it axle shaft came out with the wheel. Did the internal C clips come off inside?

 

[waterpirate]

I totaled a corn biner with a tool body when that happened to me. Passenger side axle and tire came out, tried to pass me. Instead the axle speared between the back of the cab and the tool body, piercing the gas tank. Since I was already sliding on the brake backing plate and sparking like Ricky Bobby. I burst into flames. I put it into a wet ditch and bailed out.
Glad you are O.K. and not becoming Ricky Bobby like me.
Eric

 

[Pmcb]

Thanks for the encouraging words. I think the c clip must have come off, the shaft end still looks pretty good accept for damage bouncing down the road. It did not snap in half, and shows no signs of breaking. The wheel and shaft did hoist the drivers side door and there is a small dent in the door pillar. But could have been much worse for me or someone else on the road.

 

[GTX63]

I think the guy in this video was going to do a simple bearing swap until he discovered the rear end was total trash and probably 1 mile from doing the same thing your truck did. Without any bearings, that little C clip doesn't have much help.

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[Craig Nedrow]

Yep happened to me in a 53 chevy, Grand canyon long ago. Replaced the bearing and on my way, drove it like that for years, all good. However it would be good to put it between centers to see if it is bent.

 

[Pmcb]

I final got it home and took a good look. There is a hole in the differential cover, gears broken. Good news the the only other damage is drivers side door.
How can I tell what the gearing is so I can replace the entire rear en? I would assume it is original.

 

[Turbo4whl]

How can I tell what the gearing is so I can replace the entire rear en? I would assume it is original.

Count the teeth on the ring gear. Divide that number by the number of teeth on the pinion gear. That will give you ratio, ie. 3.07, 3.42, 3.73, 4.10:1 etc.

 

[bucket]

I final got it home and took a good look. There is a hole in the differential cover, gears broken. Good news the the only other damage is drivers side door.
How can I tell what the gearing is so I can replace the entire rear en? I would assume it is original.

I was going to say, both axles coming out is likely from a broken carrier. Axle C-clips can't just fall out unless something else goes wrong. I'll bet the truck is equipped with a G80 Gov-Loc as well, which is why it all went kaboom. People like to talk about how the 10bolt version of the Gov-Loc isn't as bad as folks make it out to be, but it didn't get the nickname of "Gov-Bomb" for no reason.

 

[AuroraGirl]

I was going to say, both axles coming out is likely from a broken carrier. Axle C-clips can't just fall out unless something else goes wrong. I'll bet the truck is equipped with a G80 Gov-Loc as well, which is why it all went kaboom. People like to talk about how the 10bolt version of the Gov-Loc isn't as bad as folks make it out to be, but it didn't get the nickname of "Gov-Bomb" for no reason.

ive heard later versions from the late 90s and early 2000s are better but all im gonan say is im glad my 1996 c1500 has a 3.73 open diff 10 bolt lol.

 

[bucket]

ive heard later versions from the late 90s and early 2000s are better but all im gonan say is im glad my 1996 c1500 has a 3.73 open diff 10 bolt lol.

I've seen the later years blow up too. Not offroad trucks either, just basic soccer mom SUVs.

 

[K10Keith]

It’s a lot easier to replace the whole rear end, with a known good axle with the same gear ratio, than to get into fixing your internals. Simply swap it out. I had what you had happen with my 1985 10 bolt, back in high school. Drivers side axle with tire rolled away downhill while I stopped moving uphill. I’d upgrade, while you have the chance. Junk yard rear ends, in my area are $250-$350 complete. The likely worst you might need to do is add a brake job, if needed, and replace the gear oil. An easy Saturday project.

 

[justhorns]

Ratio is usually stamped on the outside of the ring gear. Zoom in and you can see 13 40 next to GM 40 teeth on ring gear, 13 on Pinion, 40/13 =3.08

 

[Pmcb]

I am really struggling with getting the gear ratio. Nothing on body, doors, glove box…. Cannot turn anything in rear end, looks like the ring is 41, pinion looks to be 15, but this is from eying half way and doubling the number. I could be off a couple either way. If I’m right it is 2.73. If not, calculate being off one or two either way it does not come out to any known gear ratio. Is there anything else I can do short of pulled my tea end apart?

 

[bucket]

I am really struggling with getting the gear ratio. Nothing on body, doors, glove box…. Cannot turn anything in rear end, looks like the ring is 41, pinion looks to be 15, but this is from eying half way and doubling the number. I could be off a couple either way. If I’m right it is 2.73. If not, calculate being off one or two either way it does not come out to any known gear ratio. Is there anything else I can do short of pulled my tea end apart?

You can pull the front cover and look at the numbers stamped on that ring gear. It's a good excuse to change the gear lube that is likely original.