Rear Axle Swap Question for a 2005 3.7L Auto 4WD

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Phyrmn

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I apologize if this question is redundant, I've been searching through threads most of the day. I'm looking to swap out a noisy rear axle on my 2005 3.7L Auto 4WD. I bought the jeep from a GOV sale a few years back knowing that the rear diff had issues. I replaced the axle/pinion bearings and seals bought a micrometer and set the lash as best I could. Unfortunately the rear diff is now making more noise. I'm just looking for a little info. If I hit a Pull A Part can an axle out of a 2007 with the same 3.73 ratio work in the 2005? My 2005 doesn't have ABS. I'm just looking to replace the rear end with something with the less miles on it as possible. An axle swap is considerably less time consuming versus going back into the rear diff. Any info is greatly appreciated.
 
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lfhoward

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That sounds like a good plan to me. I would think a 2007 axle in a non-abs 2005 would work fine, but it wouldn’t work the other way around (2005 in an 07). You can probably cut the wires to the wheel speed sensors, but leave the sensors in the axle to plug the sensor holes. Take a look at whether or not you have a physical speedometer cable that goes back to the rear diff. The 07 would not have this, and would instead use the wheel speed sensors for mph data.

This would be a good time to replace the stock rear control arms with beefier ones from Iron Rock Offroad, and consider a lift or new shocks and springs.
 

Phyrmn

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Thnk you for the reply. Mine has the sensor in the rear diff, so using a 2006 or 2007 rear axle is going to be impractical I'm afraid. So I guess I go looking for a 2005. Thanks again for the info.
 

LibertyTC

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^Yup 2005 or earlier diif ^
Any differential shop should be able to inspect it for lash etc.


I wonder if the noisy rear diff may also contain the Trac-Lok?
Some of the KJ rear diff's came with a clutch based Trac-Lok, which required adding a 4 oz bottle of Mopar friction modifier.

Check your build sheet to see if it has the Trac-Lok.
https://fcagroup.my.site.com/RAM/s/equipment-listing
 
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Phyrmn

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No Trac-Loc in mine it's an open diff, just wore out I guess. Thank you all again for the help, I'm headed to Louisville Pull A Part this morning to see what I can get.
 
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Phyrmn

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Update: I pulled a rear axle assembly out of a 2004, unknown mileage. This one was my only viable option with what Pull A Part had in there yard. I attempted to pull the cover off of the rear diff to inspect it, but half of the cover bolts were rounded off. It had a ton of RTV on it so someone had been inside it at some point or another. Loaded it up and brought it home. Was able to remove the remaining bolts here at the house. Then found *see pic* stuck on the magnet. I have no idea where this would have come from, other than "maybe" someone had some type of locker in it before? Any ideas?
 

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lfhoward

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Update: I pulled a rear axle assembly out of a 2004, unknown mileage. This one was my only viable option with what Pull A Part had in there yard. I attempted to pull the cover off of the rear diff to inspect it, but half of the cover bolts were rounded off. It had a ton of RTV on it so someone had been inside it at some point or another. Loaded it up and brought it home. Was able to remove the remaining bolts here at the house. Then found *see pic* stuck on the magnet. I have no idea where this would have come from, other than "maybe" someone had some type of locker in it before? Any ideas?
My first thought was a lunchbox locker too. Maybe it blew up and they put the spider gears back in? But they didn’t get that spring out. Hopefully there wasn’t any other debris.
 

Phyrmn

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The gears looked good, no wearing or scarring visible. The flange isn't completely round like my 2005, so I'm hoping it bolts up with little issue.
 

Phyrmn

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Just a follow up. I was able to replace the axle, everything went fairly well. Working by yourself does have it's drawbacks. But anyway, everything is better now, less slop and less whine. I do believe the pinion bearing is making a little noise, not like the original axle anyway. Currently into replacing the front cv's, so pinion noise will have to wait for just a little while. Other than that all is good. Thanks for listening and offering up some very helpful information.
 
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