Gears and rear end

by **Alan Lotarski (Sean)** » 24 Feb 2002 14:11

How do I know what gears and what size rear end are in my T/A? I have decoded the fender tags but nothing on gears or rear end. help?

by **Gord M (Gord)** » 24 Feb 2002 14:37

The code appears on the build sheet.
076 = 3:55
077 = 3:91
These parts codes were also painted in yellow onto the rear end axle tube. They are the only gear ratios available for a T/A AAR.

Also, there was a small metal tag bolted on the centre pot when it was installed originally that has the gear ratio stamped on it, it may still be there.

Other than hoping the original gears are in it and checking the stamping on the ring there's no other way to tell that I know of.

by **Dave R (Roppa440)** » 24 Feb 2002 16:23

It's an 8 3/4" rear (the exact type is cast into the pinion casing) and you can jack up both wheels (limited slip diff) or one wheel (open diff) and count how many times the driveshaft rotates to one wheel revolution.

You can tell if it is limited or open diff by lifting both wheels and turn one by hand. If the other wheel rotates in the same direction you have a limited slip diff. Opposite way means you have an open diff.

I would have thought all T/As came with limited slip "SureGrip" diffs though Gord eh?

by **Gord M (Gord)** » 24 Feb 2002 18:27

You're right Dave, all T/A AARs came with Sure Grip in a "489" case.

by **Alan Lotarski (Sean)** » 25 Feb 2002 14:28

where on the build sheet is it? What line and under what word?
thanks
alan

by **Alan Lotarski (Sean)** » 25 Feb 2002 16:21

There are no numbers like those on my build sheet.Axle is 078

by **Gord M (Gord)** » 25 Feb 2002 17:19

Sorry, my memory isn't what it used to be :
Build Sheet will have
D56 - 3:55
D57 - 3:91

Dave has an option decoder on the Challenger Home page. You should be able to decode the entire build sheet using it.

by **Dave R (Roppa440)** » 25 Feb 2002 19:16

The code Gord is talking about here is on line two of the build sheet just under the sequence number. The code you found is on line four and is the last three digits of the axle part number.

by **Alan Lotarski (Sean)** » 25 Feb 2002 19:54

I got it. It is D57 3.91:1 I had found 2 build sheets folder together between the springs and foam in the back seat. Only one of them is for my car. The other is for an R/T.It figures the one that is for my car is in pretty poor shape it was the outside one and can't read all of it but almost all and the R/T is perfect.

by **Jack T (Jackt)** » 25 Feb 2002 21:07

Please post the R/T's VIN - you might help someone out who has the car but not the build sheet.

by **Alan Lotarski (Sean)** » 27 Feb 2002 13:29

Here it is.JS23N0B212440

by **Mopar Racer 70** » 07 Jan 2013 1:31

Old post I know but I am the owner of that RT would love to know if the build sheet is still around

by **dave-r** » 07 Jan 2013 8:43

With luck he might have sent it to Barry Washington as he runs a "lost and found" for buildsheets. Although I just did a quick search of his website and couldn't see it.

Might be worth asking him though in case he knows where this Alan Lotarski is.

http://www.hamtramck-historical.com/

by **Mopar Racer 70** » 07 Jan 2013 22:41

Thanks for looking. I do check on Barrys site once and awhile just to see if anything has been found. I will send Barry a message to see if Alan maybe registered the T/A he was working on.Thanks Again

by **dave-r** » 08 Jan 2013 11:55

Good luck.