C6 casting numbers?
 

Im going to be putting a C6 in my '84 Bronco for the time being. Today I was changing the filter on it I found some numbers on the back of the tranny, by the tail shaft, They are:
3 356A1 76617 A

I also found on the valve body these other numbers:
D7AP-7A101-AA
LESTER-3

Mainly concerned about the numbers cast into the transmission housing by the tailshaft. Thanks for any imput. Hoping to find out what year C6 it is so I put the right ATF in it.

D7AP is 1977 fwiw, which ain't much.

Look for a date code in this format: "7/2011".

Alright so she's a '77 C6 then cool... today when I was giving the C6 a good cleaning before I put it in, I found a tag with another set of numbers on it:

PGD DL1 M23
E1TP CA 023674

I found these on a tag on a bolt that bolts on the servo on the passenger side of the tranny. Just wondering if there is a site I can go to to decypher these numbers? Thank you.

1977 was the first year for Mercon/Dexron fluid in C6's;
76 & earlier used Type F (unless rebuilt with later clutches, bands etc).

The E1TP number is from 1981

Thank you Ken. Would those numbers tell if it is a 3 speed or 4 speed? Im really hoping its a 4 speed with overdrive.

A C6 is ONLY a 3 speed non-OD, non lockup trans.

Im not to keen on AT lingo, non-lockup trans meens what again?

It means the torque converter doesn't have a clutch inside it. It slips all the time.

I thought sliping was bad as it wears things out quicker?

It isn't sliping like clutches can do. A tc is a hydraulic cuppler so there no possitive/ mechanical lockup. There will always be some degree of slip in a tc.

If you want to know more about torque converters and lockup clutches there is a good article at HowStuffWorks - Learn How Everything Works!

As 85e150six4mtod said, the C6 is only a 3spd, but it's a much better suited transmission to a truck, or any hard working vehicle, than an AOD or AODE (which were 4spd's). The C6 is much heavier duty, simpler, & less expensive to eventually rebuild.

I've had each in my truck & I prefer the way that the C6 operates.

But the C6 is old-school (an auto-trans mechanic I know calls them "agricultural" :D) & doesn't have the economy of either lockup or overdrive, if that's what you need.

Those casting numbers are Ford engineering numbers and not when it was made! But Either way Mercon of Type F will be fine in the unit and Type F provides firmer shifting with less slippage!

That is true, but note that an "E1.." casting is going to be NO OLDER than 1981, or a "D7.." NO OLDER than 1977.