70 LT-1 Differential

[Tim S.]

I would like some help with the information on the rear diff in a 70 LT-1 I just purchased. The car has a build date of 3-5-70 and does have the original motor 2-23. The rear end has the HD yokes but I am a little confused with the stampings. It reads OA 006 E1. Thats it. I question if it could be the original due to the fact the car does not have the original transmission. The diff looks like it could be original based on the patina matching everything else. Any thoughts?

Thanks,

Tim

[Steven C.]

Re: 70 LT-1 Differential

Tim, what is the MDDY casting date?

[Gary R.]

Re: 70 LT-1 Differential

70 had 3 letter stampings,only year I believe that did.

[Chuck S.]

Re: 70 LT-1 Differential

I would like some help with the information on the rear diff in a 70 LT-1 I just purchased. The car has a build date of 3-5-70 and does have the original motor 2-23. The rear end has the HD yokes but I am a little confused with the stampings. It reads OA 006 E1. Thats it. I question if it could be the original due to the fact the car does not have the original transmission. The diff looks like it could be original based on the patina matching everything else. Any thoughts?

Thanks,

Tim

From the 70-72 TIM&JG: "The differential production code for 1970 consisted of a number (for the shift that produced the unit), three letters that are the ratio code, the date produced (month 1-12/day/year), and a suffix letter for the plant that produced the differential." No distinction is made for engine option; the format above fits my base engine differential stamp perfectly.

Your differential stamp varies from this format. Others will have to say if this is an original Corvette differential, factory substitution, or a "restoration" differential. The E, at least, is for Eaton (my diff was from Warren), and the numeral 1 could be the shift. Anything beyond that is guessing unless you left out some alpha characters...I would normally expect a three letter stamp for the axle ratio.

[John H.]

Re: 70 LT-1 Differential

Tim -

The "OA" ratio code was only used in '76-'77, for a 3.08 Posi axle, with a Julian date ("006" would be January 6th). What's the casting date on the driver's side, behind the camber strut bracket?

[Tim S.]

Re: 70 LT-1 Differential

Tim -

The "OA" ratio code was only used in '76-'77, for a 3.08 Posi axle, with a Julian date ("006" would be January 6th). What's the casting date on the driver's side, behind the camber strut bracket?

John,

You are right, it's a 76. Thanks everyone. Does anybody have a CFA housing that needs a new home?

Thanks,

Tim

[Joe L.]

Re: 70 LT-1 Differential

From the 70-72 TIM&JG: "The differential production code for 1970 consisted of a number (for the shift that produced the unit), three letters that are the ratio code, the date produced (month 1-12/day/year), and a suffix letter for the plant that produced the differential." No distinction is made for engine option; the format above fits my base engine differential stamp perfectly.

Your differential stamp varies from this format. Others will have to say if this is an original Corvette differential, factory substitution, or a "restoration" differential. The E, at least, is for Eaton (my diff was from Warren), and the numeral 1 could be the shift. Anything beyond that is guessing unless you left out some alpha characters...I would normally expect a three letter stamp for the axle ratio.

Chuck------


I think that all 1963-79 Corvette complete carrier assemblies were manufactured at the Warren, MI Gear and Axle Plant. Eaton manufactured most of the positraction and non-positraction differential units used as a component of the carrier assemblies, except for those used during the 63-64 model years.