Author Topic: Trying to make sense of these Axle tube markings  (Read 906 times)

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Offline pwrcat4000

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Trying to make sense of these Axle tube markings
« on: May 11, 2021, 06:09:57 PM »
2    PJ  G322 8?  1
It is on a 1979 Trans Am (my sons) he wants to decode it for his youtube channel
I think this is a
2PJ = 2.41 standard  (open)
http://www.teufert.net/pontiac/rears.htm
The counting method seems to confirm this 2 wheel rotations is about 2 1/2 on the pinion
The axle "acts like limited slip" spinning one wheel does not seem to effect the other wheel
I have not pulled the diff cover yet

322 made November 18th 1978 Saturday? or  November 18th 1979 Sunday?  making axles on a sunday????
on Day shift = 1
I have no idea what the 8 symbol means  1978? is it some other stamp
unsure about the G
G = Detroit Gear & Axle   
G=Chevrolet Gear and Axle
G = Detroit G&A Positraction Carrier



Thanks any help is appreciated
 
My 1978 T/A the only thing that I ever loved that didn't leave me (Yet)

Y88

Offline pwrcat4000

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Re: Trying to make sense of these Axle tube markings
« Reply #1 on: May 12, 2021, 02:39:34 AM »
Build sheet is from under the gas tank and hard to read but you can defiantly see
GU2 2 second character (looks like a 1) 3rd is unreadable
so this may be PU - 2.73 Rear Gear (Posi)
next line on build sheet is hard to read but you can defiantly see POS(unreadable)XLE
My 1978 T/A the only thing that I ever loved that didn't leave me (Yet)

Y88

Offline Aus78Formula

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Re: Trying to make sense of these Axle tube markings
« Reply #2 on: May 12, 2021, 04:01:43 AM »
Looks like you pretty much have it covered. Is it actually a TA? Or original rear axle?

Offline RENOVATIONS

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Re: Trying to make sense of these Axle tube markings
« Reply #3 on: May 12, 2021, 07:40:01 AM »
Jeff

Projects:
_____________
1978 Trans Am
1970 Camaro
1970 'Cuda

Offline pwrcat4000

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Re: Trying to make sense of these Axle tube markings
« Reply #4 on: May 12, 2021, 07:19:46 PM »
Thanks for responding Aus78Formula and RENOVATIONS
Ok so this is weird Build sheet is from under the gas tank and hard to read but you can defiantly see 2PU at the top
Down in the RPO codes
GU2 2 second character (looks like a 1) 3rd is unreadable
so this may be PU - 2.73 Rear Gear (Posi)
next line on build sheet is hard to read but you can defiantly see POS(unreadable)XLE 
I guess I will have to pull the diff cover to be sure. "Probably needs changed anyway"  Is something I find my self saying a lot! LOL
« Last Edit: May 12, 2021, 07:22:17 PM by pwrcat4000 »
My 1978 T/A the only thing that I ever loved that didn't leave me (Yet)

Y88

Offline pwrcat4000

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Re: Trying to make sense of these Axle tube markings
« Reply #5 on: May 17, 2021, 11:20:18 AM »
confirmed 2PJ = 2.41 standard  (open)
My 1978 T/A the only thing that I ever loved that didn't leave me (Yet)

Y88

Offline Aus78Formula

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Re: Trying to make sense of these Axle tube markings
« Reply #6 on: May 17, 2021, 07:18:51 PM »
Date and Open confirm rear swap in a 79 TA. Look around under the rear fenders for any panel repairs since swapping to an open 2.41 wouldn't likely be by choice, rather just one they had or at short notice perhaps.

The unreadable bit is likely something similar to Posi-traction Rear axle.
« Last Edit: May 17, 2021, 07:21:58 PM by Aus78Formula »

Offline pwrcat4000

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Re: Trying to make sense of these Axle tube markings
« Reply #7 on: June 01, 2021, 06:53:05 PM »
Date and Open confirm rear swap in a 79 TA. Look around under the rear fenders for any panel repairs since swapping to an open 2.41 wouldn't likely be by choice, rather just one they had or at short notice perhaps.

The unreadable bit is likely something similar to Posi-traction Rear axle.
Well you buy something out of a junk yard maybe someone took the original and swapped this one in
My 1978 T/A the only thing that I ever loved that didn't leave me (Yet)

Y88

Offline Aus78Formula

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Re: Trying to make sense of these Axle tube markings
« Reply #8 on: June 01, 2021, 10:26:31 PM »
The date seems to work, have you checked if in the internals match? Perhaps the J/U is a mis-stamp. And based on the fact that in '79 all TA's still came with Posi diff, others will confirm if that was no longer the case like in the final years.

The buildsheet says 2PU rear ratio up in box 11 for Axle, that would be the preferred option and make it correct. The stamp does look like a J, under the red, rather than an angled-U strike.
« Last Edit: June 01, 2021, 10:30:25 PM by Aus78Formula »

Offline Maxthe222

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Re: Trying to make sense of these Axle tube markings
« Reply #9 on: June 02, 2021, 10:53:48 AM »
How do you know if it is a 2.41 just by looking at the code etched into the gears?
'79 Y84 WS6 T/A
'79 W72 WS6 F/A
'71 FRMLA 400/4-Spd

Offline Aus78Formula

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Re: Trying to make sense of these Axle tube markings
« Reply #10 on: June 04, 2021, 12:52:11 AM »
It has GM part number, date and ratio.

Here's a 2:41 Posi I had.

Diff 241 Posi 17 41 1252065 by Aus78Formula, on Flickr

Part number GM #1252065 for those who want to look up or google. Ratio 17:41 which is 2.41.... and date code 2/79.
« Last Edit: June 04, 2021, 05:12:52 AM by Aus78Formula »

Offline Maxthe222

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Re: Trying to make sense of these Axle tube markings
« Reply #11 on: June 04, 2021, 09:57:37 AM »
It has GM part number, date and ratio.


Part number GM #1252065 for those who want to look up or google. Ratio 17:41 which is 2.41.... and date code 2/79.

Ok, excellent, I have a bunch of 10-bolt centres lying around and I wanted to figure out where they came from
'79 Y84 WS6 T/A
'79 W72 WS6 F/A
'71 FRMLA 400/4-Spd

Offline Aus78Formula

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Re: Trying to make sense of these Axle tube markings
« Reply #12 on: September 08, 2021, 10:39:31 PM »
A bunch? Way too much time on US car forums, next you'll be saying they Pop.