Another axle question

I searched the C/K forum and didn't find my answer.
I just bought (today) an '89 Z71 with a 350 and auto trans. Its in great shape for its age, the PO had several reciepts for anything you can think of.
The story goes....He let his brother-in-law borrow it and while going down the road the rear axle locked up on him. When I went to look at it, the truck rolled fine....in park. The drive shaft just spins and makes a rakeing sound when in gear. (locked in 4hi made it on the trailer just fine) It has just under 200k on it.
I have yet to pull the cover and have a look. Is there a common problem with these rear ends? I never seen one fail like this unless it wasn't set up correctly to begin with, and with 200k miles, it should have failed long ago it that was the case. It doesnt appear to ever had a snow plow on it, nor a hitch.
Just a case of abuse? Common problem? Neglect?
Thoughts?

i had a 1990 chevy do the same thing with me..the cross pin in the rear end broke into 3 pieces...only way to tell is to pop the cover

the cross pin in the rear end broke into 3 pieces...
Pulled the cover today, thats what I found. The carrier blown out at the pin too, like they were spinning the tire (open rear end) and it finally caught. I have been searching for a new rear end anyway. I think the housing could be reused, but I'll have more in rebuilding it then buying an entire limited slip equipped axle from a yard.

If you go another rear end on a 4W always match your gear ratio.
Here is a site with some rear end info.
http://www.differentials.com/install.html

....been lazy working on this. I found another axle, I am picking it up this weekend.
Whats the chances of the "GU6" having a limited slip in it? or is that another axle code?

Best to pull inspection plate and look and check gear ratio.
Sometimes they get change around.

yes the 88 and up axles are known for breaking

we had to replace the rear in a cousins 95 k1500 pickup that broke on him

something about the 88 and up rears are weaker

dont know what

but its happening




good luck

Thanks fellas...
I thought I had that axle I was referring to. That bleep bleeping bleep bleeper strung me along. Kept spinning a line of B.S. One weekend its this, next its that.
I even passed over a front and rear matched set out of a newer truck with LESS miles because I thought I had this one....:banghead: (didn't know the ratio is what stopped me)

So today, I welded basically everything inside the carrier to itself. (welded the chunks back in) This way I at least can move it around my property..(axle kept coming out since the cross pin wasn't in)

....NO I am NOT going to drive it down the road like this. (and further proof is the numbers on the sign at the local gas station :banghead: )