Can I use a differential from a 88 or 89 sierra in my 82 silverado?

[team39763]

They are both 8.5 10bolts but mine has the G80 and his doesn't.  I'm really just wanting to give him my G80 since he'd love to have a posi.  I should be ready to drop in the 12bolt soon.  He's a cool guy, so I figured I'd let him have it rather than me breaking it or throwing it away.  But a couple of my neighbors told me that the 88+ truck diffs were 30spline while ours are 28.  Is that true?  I know the 99+ are 30spline, but I thought 88-98 were the same as ours.

[zieg85]

I had a guy purchase a 12 bolt I had out of a 76 I was selling for a friend.  The guy told me he had measured them up and said it would work.  He was putting it in a 1990.  Can't tell you for sure though if he had to make any modifications to it.   

[HAULIN IT]

Team, The way I believe it is (don't take this for fact if someone else says differently) the '88-'89 Blazer/Subs (our body style) are 28 spline. The new style '88-up trucks are 30 spline. The carrier would interchange, but you would be fouled up on shafts, so it's kinda a no-go. Later ('98 or so) the carrier bearing diameter changed. Lorne

[Blue 82]

I was told the 88's had 30 spline axles also
My 88 Reg Cab short bed had 28 spline axles
I pulled an axle and checked before installing a G80

[Captkaos]

AFAIK, It is going to be hit/miss because the started using 30 in 1988 and stopped using 28 in 1989.

[Irish_Alley]

don't remember what year  the axle came out of but it was too short in my Buddy's 94 k1500. probably don't help much since you said your bud measured them up already, and i don't know the year of the axle I'm sure it came off of a mid 80's k10

[team39763]

Well, I'll see if the guy doesn't mind checking what spline his axles are. 

What is the thread size for the cover bolts?

[zieg85]

13mm is the socket size to take them off.  It is metric though, at least mine was...