Rear end question?

[Dugan]

Jacked my 67 mustang up today, put it in drive blocked the passenger rear tire from moving and tried to spin the drivers side and it wouldn't move. Unblocked the tire and they both spun in unison...does this mean I have a locked rear end?

Also what are the ways to tell if I have an 8" or 9" rear end?
Thanks.

 

[ultrastang]

If the wheels won't turn independently of each other, then it's most likely that you have a Limited-Slip differential, if it's original to the '67. --(Ford Traction-Lok differential didn't come out until 1969).

It's also possible that some previous owner could have installed the differential. If that's the case, then there's no telling what it actually is short of pulling the 3rd member and looking at it.

A quick way to tell if you have an 8- or a 9-inch is to get a 9/16" socket and a 9/16" boxed-end wrench. There are (10) nuts holding the 3rd member to the rear end housing. If the socket will not go onto either of the (2) bottom nuts, it's a 9-inch. (only an open-end wrech will easily go on them). If the socket easily slips on, it's an 8-inch.

 

[Dugan]

PO said it wasn't the original rear end. I will try putting a socket on the bottom two bolts tomorrow.

 

[dodgestang]

Did the tires spin in the same direction? Then use you have limited slip diff of some sort
Did the tires spin in opposite directions? Then no you do not have a limited slip of any sort

 

[Dugan]

yea they spun in the same direction, i was gonna try to fit a socket on the bottom two today to see if i have a 9" or 8" rear, but was at my brothers all day helping him pull the engine out of his 2000 ford f150.