BX axle code?

[L78M22Rag]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bwag</div><div class="ubbcode-body">Looks like I'm showing up late to the party . Spring break and away from the computer .I should be able to clear up the rear end mystery .Lets go back to the summer of 69,we were having trouble getting the car to launch consistently,so we were at Milan dragway on a Saturday trying different methods. Well after the third launch neutral starting I shattered the origional rear end,it had a 4.56 gear from the factory,the ring and pinion ,left axle and housing were destroyed on the launch.We winched the car back on the hauler and went back to the shop. Seeing that only the right axle was salvageable we pulled the assembly out. The parts dept had a warranty axle assembly with a 4.88 posi laying on the floor . We had it installed in the car and back at the strip on Sunday morning with No Neutral Start written on the dash!So the rear end in the car is not the origional . </div></div>

I guess that probably answers my question too. Thanks, and sorry for chiming in on your thread.

[Ryan1969Chevelle]

Any L78 Chime is a good Chime.

Ryan

[L72copocamaro]

My 05C 4:88 had a Feb date code.

[Kurt S]

Bob,
Thanks for clearing this up.

Yes, to get a 4.56 or 4.88 in a Camaro, it was a COPO order.

Comparing it to other models / years isn't really a valid comparison since the ordering method changed. The data on other 69's says this axle date was *way* off - I've always been surprised by how close the dates are on some unusual components in 69.

[MosportGreen66]

Thanks for explaining the rear end situation Gents

Always impressed with the knowledge around here!

[mockingbird812]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mockingbird812</div><div class="ubbcode-body">Very interesting. Nice score Jeff (altho a decades old score) [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img] <span style="font-style: italic"><span style="font-weight: bold">Would the 4.56 &amp; 4.88 gears get the hardened pinions like the COPO 4.10 rear ends? I would hope so! </span></span>[img]<<GRAEMLIN_URL>>/shocked.gif[/img] </div></div>


Sooooooo.......... [img]<<GRAEMLIN_URL>>/whistle.gif[/img] ......... anyone know if the R&amp;P were hardened in a COPO ordered '69 4.56 or 4.88 axle ratio like the 4.10 gears were in a 9561 optioned Camaro?

[ss427copo]

Yup.....they sure were. Stamped high impact.



Of course, not High Impact enough for Ol Yeller's 7400, 1st to 2nd upshiftsthough! LOLOLOL

[ss427copo]

Thanks Bob for clearing up the BX question.
It is nice to be able to say, &quot;hmmmm, I wonder about this, let me check with the guy who ordered the car&quot;

[Kurt S]

I don't believe the factory gears were stamped high impact. Just the ordering changed, not the gears.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ss427copo</div><div class="ubbcode-body">Yup.....they sure were. Stamped high impact. </div></div>
Those don't appear to be the original gears. I see a date on the ring gear of 3 70.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bwag</div><div class="ubbcode-body">Jeff , Did you notice the date code on your broken pinion gear June 69 ? We had 4.56,4.88,5.13 and 5.38 gears in and out of the car over the years. The 4.88s seemed to be the best combo overall.Some of the gearsets we used were the hi impact gears. Bob </div></div>
I don't see a June date - I think that's the part #. Just a date on the ring gear of 3 70 (7 is hard to see) and maybe the same date on the pinion, but I can only see the month code (3).

[mockingbird812]

So Kurt, are you saying that a 9561 ordered '69 Camaro would get the hardened ring and pinion for the 4.10, but not a 4.56 or 4.88? Are 4.10 R&amp;Ps ordered via the COPO 9561 stamped &quot;high impact&quot;?