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  • May 12, 2024, 12:58:15 PM

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Author Topic: Posi differential.  (Read 5300 times)

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Offline rmick

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Posi differential.
« on: September 02, 2014, 09:39:00 PM »
Would there be any problems with running a limited slip in one differential and not the other?
72 Javelin AMX
72 Javelin SST
72 Gremlin with 4.0
81 SX 4

Offline captspillane

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Re: Posi differential.
« Reply #1 on: September 03, 2014, 07:53:16 AM »
A limited slip is a good thing in the rear and can be there all the time, 2WD and 4WD. In the front it will be noticeable while you drive, similar to the way a Jeep Cherokee has noticeable binding and resistance while in 4WD.

The transfer case itself has a differential to allow the front and rear to slip in relation to each other. The Viscous Coupler is a weak form of limited slip differential. Changing to a NP242 gives you the option either fully open or fully locked differential in AWD or 4WD.  Putting one of those in with limited slip in the rear you will basically have at least one front wheel spinning at all times and both rear wheels spinning at all times. That's three wheels workinger where in comparison the stock setup can have a single wheel spinning for quite some time before the front slowly tries to engage. There will be a major traction gain over the stock setup.

The front axle does not have a limited slip carrier that will work without modification, but I've heard of several people making it work by changing the clip somehow.
Currently Inspected and Insured as of Jan 2013:
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Offline carnuck

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Re: Posi differential.
« Reply #2 on: September 05, 2014, 12:12:33 AM »
Only if it's in the front and not rear with a rear biased 4x4 system. I have a ZJ D35 with some kind of posi that was rebuilt @40K ago and 3.55 gears that will need spring pads and shock mounts (It's drum brake) but I'll be lucky to get $250 for it. Going with an XJ 8.25 is better for me since I won't have huge tires.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline rmick

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Re: Posi differential.
« Reply #3 on: September 06, 2014, 06:51:12 PM »
Looking through the AMC maintenance manual it says a twin grip diff was available for all models except Eagle. Was thinking about putting in a limited slip in the rear of the Eagle from a Spirit with an AMC 15 twin grip diff. Just wondering why it was not offered as an option for the rear diff for the Eagle.
72 Javelin AMX
72 Javelin SST
72 Gremlin with 4.0
81 SX 4

Offline carnuck

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Re: Posi differential.
« Reply #4 on: September 06, 2014, 08:51:59 PM »
Because they didn't think it was needed with a viscous coupler in the tcase. 1 tire front and back had to spin to get stuck.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline rmick

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Re: Posi differential.
« Reply #5 on: September 06, 2014, 10:30:38 PM »
 I would rather have two wheels in rear spin than just one.
72 Javelin AMX
72 Javelin SST
72 Gremlin with 4.0
81 SX 4

Offline carnuck

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Re: Posi differential.
« Reply #6 on: September 07, 2014, 12:01:19 AM »
Me too, or better yet, locked front/rear with posi rear and air locker front.
AMC/Jeep gauges are for amusement only. Any correlation between them and reality is purely coincidental!

Offline eaglefreek

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Re: Posi differential.
« Reply #7 on: September 07, 2014, 12:32:04 AM »
A limited slip was offered on the Grand Wagoneers with the NP229, so I don't think there would be an issue. I had a 8.25 with LSD in mine for about 3 years without any issues.
1986 AMC Eagle Wagon 4.2L/4.0L head, AW4,NP242, Chrysler 8.25" rear.
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Offline rmick

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Re: Posi differential.
« Reply #8 on: September 07, 2014, 12:46:11 AM »
Good to know I already have the 229 in my Eagle. Now if I could only figure out how to make an air locker for the front axle. 8)
72 Javelin AMX
72 Javelin SST
72 Gremlin with 4.0
81 SX 4

 

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