rear end/tranny number help please...

[rick spears]

can any one decipher these numbers off of my new project?

rear end: 1AU6468 W

trans:(the only thing i could find) PO 828

thanks for looking, and HAPPY EASTER EVERYONE! rick

[John H.]

Re: rear end/tranny number help please...

Rick -

The diff is a big-block 3.36 Posi, assembled on June 4, 1968 at Warren. The trans was assembled at Muncie on August 28th.

[rick spears]

Re: rear end/tranny number help please...

well, that's good news. this is a 68 coupe....no motor, but was told that it was originally a 427/390hp car. how can i determine what year of tranny i have? it is a muncie 4 speed. where would i look for the VIN on it? the numbers i posted are on the right side flange between body/tail shaft joint. thanks!

[John H.]

Re: rear end/tranny number help please...

Rick -

If it's original to the car, it should have a 3925660 main case, 3857584 tail housing, 3884685 side cover, and should have the last six digits of the car's VIN, preceded by 8S, stamped vertically on the driver's side on the rib at the rear of the main case.

[rick spears]

Re: rear end/tranny number help please...

thank you john....i didn't see a vin, but i'll look again, and check the casting numbers.....thanks, rick

[Anthony S.]

Re: rear end/tranny number help please...

Rick,

Neither did I the first 3 times I looked. Mine was covered in years of "stuff." I used a soft brush & some brake cleaner to reveal it, it was to the left of the stamped date on the case.

As for if it's an M-20 or M-21, I don't think you can tell from the outside, they used the same case.

In 1969 they added letter to the end of the date code to identify the trans; A=M-20, B=M-21 & C=M-22.

Good luck,

Anthony