4.10 axle with LSD

[Wietse]

Gents,

Today, looking in the mirror after making a small burnout i observed 2 beautiful black tire marks...
So after i came home i lifted the ***-end and checked the rear axle to see if there is a LSD installed.
Both wheels rotate in the same direction and when blocking either side wheel will lock up both.
That's a good thing to know.
While i was at it i wanted to know the ratio as, which i found out is 4.10:1. (explains its fuel consumption as well)

So knowing this, the cast numbers on the housing are as follows:

2881489, also a BIG 9 can be seen on the same side of the housing.
This is a 8-3/4" housing, according me this setup will not be original right?
Or did they have this housing from factory with this ratio and lsd?

 

[Sixpactogo]

It is a factory set-up depending on what year your vehicle is and I think it would have been a special order to have the 4.10 gear.
Most of the cars with the 489 case would have had either the 3.55 or 3.23 gear unless special ordered

 

[66Satellite47]

IIRC 3.91's were somewhat common & I do think the 4.10's were available in the '69 vintage 489 carriers. Might have been a special order. Seems like special orders happened more than I ever realized at the time.

Or it's aftermarket setup.

 

[Wietse]

Yeah, i forgot to mention it is for a '69 Coronet R/T.
It does have a 26" radiator but to me it looks like the previous owner cut a piece out of the radiator support so it probably came from factory with a 22" radiator and a stock 3.23 ratio and someone either installed a original lsd gear setup or went aftermarket with the original case.

Only way to confirm that is to open it up, which i might do this winter.