I would like to date my Turbo400 and 12 bolt limited slip ...

[Zone47]

.... to see what year they are.

I tried waving flowers at them but they don't seem interested.

(sorry, had to get that out of the way).

I'm pretty sure the truck (68 C10) came with a 6 popper and 3 speed on the column, so the turbo 400 is out of something else and I doubt they would put a 12 bolt into a 6 cylinder truck.

Anyone know where the numbers are on either and how to decode them? Thanks.

[jessemthompson]

I don't have the answer for deciding your trans, but I can certainly tell you that the 12 bolt in your truck is more than likely stock. Chevy did put 12 bolts in 6cyl. trucks.

[GR8-68]

Jesse is correct, the 12 bolts was probably one of the most common rear axles in this era of truck including the 6 with 3 You should be able to look the code up for each and be able to know the year.

[halfstep]

There is a small aluminum ID on the passenger side of the trans that will get you all the information you want. You'll just have to look up the codes online.

[DeadheadNM]

Fwiw my 72 Blazer has its original th350 and it does not have an ID tag - the date code is stamped into the oil pan as shown here: http://67-72chevytrucks.com/vboard/s...8&postcount=60

[Zone47]

How surprising on the 12 bolt, and how cool is that! It's a tall gear I think. I spun the driveshaft 3 times and the wheels only went around once (wheels going the same direction).

Thanks, I'll climb under today and see what I can find out number wise.