71 GS rear... Or not?

[joeskylark]

Can anyone help me identify a rear by the axle tube stamp? I was told it was from a 71 GS, but I'm not positive. The axle tube stamp is LL 00BB. 1006622. It is a posi with an eaton carrier. Any help or information is greatly appreciated.
-Joe

[Bob]

I don't know how to interpret that, but, if you look on page 40-79 here:
http://www.teambuick.com/reference/l...files/40-d.php

[bob k. mando]

weird. my books say there should be a three letter code stamp.

IF the factory double stamped all of the codes for some reason
THEN we'd be looking at an 'LOB'

which in 1971 would decode as

L == A body, 8.5"
O == 2.73 or 41:15 Limited Slip
B == Buick plant

all Buick A body rears for this year should be Buick built, while a big car 8.5" could come from any of the divisions. all of the big car 9 3/8" rears are Olds.

not exactly a drag strip gear, but you'd expect a limited slip in a GS or wagon.

[bob k. mando]

bad news from the Chassis manual:
http://www.teambuick.com/reference/library/71_chassis/


it breaks the rear codes down by engine, trans and MODEL application.

according to the chassis manual, this diff should be behind a 350ci / TH-350 ... in a 43436.

which is a Sportwagon.

otoh, shouldn't a wagon have a leaf spring rear? kind of hard to miss the missing spring buckets for an A-body Skylark / GS.


never mind, only the Estate Wagon has leaf springs, Sportwagon had coils.

http://www.teambuick.com/reference/l...files/40-a.php

something else i'm noticing though, the chassis manual thinks that all Gran Sports had a 455. i'm pretty sure that's not true.

in fact, the Stg1 registry says that the vast majority of GS production in 71 was Bu 350 powered.

http://www.buickperformanceclub.com/GSprod.htm

[joeskylark]

Bob thanks for the information. I did locate LOB under my earlier noted code. Additionally, I may have misread the code that I initially reported. Upon closer inspection, I found that instead of LL 00BB, it may be LL C0B. On the axle tube, it looks like this:

LL C0BB 1006622

LOB

this is definitely a coil spring rear, and I have seen multiple 350 GS cars.
Also, you are correct that it is a 2.73 gear.

I am trying to find new axles for this rear. I was concerned that it may have been an olds rear. Thanks for the help. Curious about your comment, "more bad news from the manual". Was that because you thought it was a leaf spring rear?

[bob k. mando]

I was concerned that it may have been an olds rear.


nope, the third letter would be an "O" if that were the case.


what i mean by 'bad news' from the chassis manual is that a 350 GS would vin code as a Skylark, the Gran Sport would just be an option package on top of that.

the problem from the chassis manual is that there is only one "economy" option ratio shown for a Skylark / Custom, 2.56:1. "LKB" for peg leg and "LTB" for limited slip.

the LOB 2.73, according to the book, was ONLY supposed to be in the Sportwagon. unless the GS package was also an option on the Sportwagon, that rules this out as an OEM 'GS' part ... unless you can find an option sheet showing otherwise.

this was before a lot of computerized automation and a lot of strange things happened that weren't necessarily "by the book".

but you've already told us this is a replacement rear anyways. just don't try to justify it as 'original to the car' and i doubt you'll have any problems. externally and even parts wise, this rear is identical to what came in the Skylark / 350ci, it's just the gear set and tube stamping that's 'wrong'.

most likely, the rear will never get looked at unless you're trying to win a concours show.

[joeskylark]

Thanks again for passing along your knowledge. I bought this rear in the middle of the night while it was raining, at a farm 250 miles away from home. I knew it was a posi with bolt in axles, and I took the guys word for it that it came from a 71 GS. I knew it needed to be rebuilt, but thought it would still cost less than having my 1970 skylark open rear converted to a posi. 8.2 parts are not easy to come by, but 8.5 parts are everywhere. My plan is to switch the gears to 3.42's and link it all to a fresh built 455. My car is a keeper. No plans to call it a GS. I just want it to be a nice cruising sleeper. I forgot to mention that it is a convertible.