Trying to identify a jag diff dana or salisbury co4hu-004-030 is the casting number

dana 30 axles should be same all same
the only problem you will have to be aware of is the diff ratios
If the ratio is not the same , there is a real risk of front and rear diff failure or failure of the transfer case
you can overcome this by putting the diff from the bent axle housing into the new housing or have a transmission shop do it for you

if it is the same bolt pattern in a banjo housing
(fit in from the drive shaft end not salisbury type-- remove cover and pull crown wheel out from the rear) it will fit
items to consider are axle spline size and numbers and diff ratios
if the ratios are not the same , the swap will cause very early drive line failures

Chevy Casting Number identification - Block casting numbers

outintheshop.com/faq/casting/castings2.htm
Chevy Block Casting Numbers. Use these casting numbers to identify the block you have. ... 283. car & Truck 2-bolt. 3790721. 64-67. 327. 2-bolt Chevy II Nova Recessed filter. 3791362. 66-67. 327 ...... Vortec Truck L-35. 12554290. 350. 94-96.

remove the axles --- remove the drive shaft . If it is a Salisbury style diff remove the plate on the front and prise out the diff carrier (Crown wheel assembly ) Undo the pinion nut --remove the pinion and pull the pinion out the front. If it is a centre that is bolted in from the back then undo all the bolts around the cast housing and pull of that way.

there will be a sticker inside the bottom of the glove box its a service tag...its a gm..build options code lable...call a gm dealer and talk to parts the will tell you ...also on the rear diff cover there also should be a metal ID tag on one of the bolts..thats the ratio and numbers also...its most likely a DANA with a 4.11 or a 3.86 ratio ..or remove the diff cover and count the teeth on the ring..then on the pinion..

Find the engine identification tag. Attached at the factory, this tag is normally found on the engine block around the coil bolts. The top line of the tag identifies engine size and model year.

Search the block for the engine block casting number. The numbers are raised, not stamped into the block and consist of seven numeric digits. The digits can be located on either side of the block. The seven-digit number may be followed with a dash and further numbers. These are change codes and are not normally necessary to identify the engine.

EX.:

Locate the casting date is located on the block. It is in standard date coding, 2.25.93, for example and may be located on either side of the block, but is commonly located on the driver's side of the block, above the freeze plugs. The example 2.25.93 decodes as February 25, 1993. The casting date may be near the casting clock, which designates the hour the block was cast. Magnum engines were manufactured from 1993 to 2002, so verifying the date code helps identify the engine.

diff unit ,EP90 that will go in all of the differentials and manual gearboxes

Jeep Axle: AMC 20

Front Axles
Dana 44
Dana 30
Dana 27
Dana 25


Rear Axles
Chrysler 8.25"
Dana 35c
AMC 20
Dana 30
Dana 60
Dana 53
Dana 44
Timken
Dana 41
Dana 23


Jeep Axles
Upgrades
Factory Options
General


-->All AMC 20s have a 8 7/8" R&P and use a 29 spline shafts. The AMC 20 R&P is 3/8" bigger than the Dana 44, but it uses smaller shafts, smaller axle tubes, and the CJ version comes with weaker two piece shafts. The AMC20 uses a 29 spline shaft where as the later Dana 44 uses a 30 spline shaft. The AMC 20 housing tends to flex a lot which can cause breakage. This can be remedied by welding the tubes and/or adding gussets. The reason the AMC 20 flexes more than the Dana 44 is the shorter differential housing and smaller axle tubes. It's other flaw is the CJ version uses the two piece axle made up of a hub and a shaft. The hub end tends to break off under load which has created the market for one piece AMC 20 axle shafts. Unfortunately, the shafts are expensive ($350+ USD) and in some cases a special bearing must be used.
-->Identifying the gear ratio of an AMC 20 is a bit tricky. Dana axles normally have a tag on the left of the diff cover with the gear ratio at the time of build. The AMC axles have a code that has to be looked up in a table. The code is stamped on the housing boss to the left of the diff cover right near the axle tube. Good part about the stamp is it tends to stay readable longer than the tag, but you have to know the code. Since there are conflicts between what a code means for a narrow track and what it means for a wide track, don't count solely on the code to identify an axle. Bring a tape measure or know the source of the part. Specs Narrow Track AMC 20 Code Gear Ratio Diff Type AA 2.73 Open DD 2.73 Trac-Lok BB 3.31 Open CC 3.31 Trac-Lok A 3.54 Open N 3.54 Trac-Lok GG 3.73 Open Q 3.73 Trac-Lok L 4.10 Open M 4.10 Trac-Lok Wide Track AMC 20 Code Gear Ratio Diff Type D 2.73 Open DD 2.73 Trac-Lok B 3.31 Open BB 3.31 Trac-Lok A 3.54 Open AA 3.54 Trac-Lok H 3.73 Open HH 3.73 Trac-Lok C 4.10 Open CC 4.10 Trac-LokThe Trac-Lok is a limited slip differential. You may have to scrape away a lot of mud, paint, and rust to uncover the code. If you can't find the code on the rear, check the tag on the front axle. Both axles should be geared the same. The R&P ratio ranges supported by the carriers are 2.73 and 3.31-5.13. The 5.13 gear ratio is not available for the Dana 30 though, so it is rare to see it. 4.56s are the lowest common ratio between the Dana 30 and AMC 20. 5.13s are available for the Dana 44.
CJ AMC 20 The CJs used two versions of the AMC 20, the narrow track from '76-'81 and the wide track from '82-'86. Both versions use keyed, two piece shaft/hub design and 5 on 5.5" wheel bolt pattern. Supplies of AMC 20s were exhausted in 1986 and some Dana 44s were used instead in the last of the CJ-7s.
From 1976-1978 a larger 11x2" drum brakes was used on the AMC 20. After 1978, a 10x1.75" drum was used.
SJ AMC 20 The Wagoneer and full size Cherokee also used a narrow and wide track version of the AMC 20. Both SJ versions used once piece shafts and 6 on 5.5" wheel bolt pattern. Since the length and bolt pattern is different from the CJ version, the SJ shafts are not compatible without resplining and redrilling. I've never heard of anyone going to the trouble.
Model/Version Spring Pads Wheel to Wheel Years AMC 20/CJ Narrow Track 36" 50.5" '76-'81 AMC 20/CJ Wide Track 36" 54.5" '82-'86 AMC 20/SJ Narrow Track AMC 20/SJ Wide Track Last modified Friday, 03-Dec-1999 21:48:34 MST
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There is a tag on the cover of the diff. It will say the type and axle ratio. If the diff. cover looks sort of like a stop sign, then it's a dana 44 rear. A oval shape(an oval on it's side) is a dana 35.