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  • February 25, 2024, 09:49:21 AM

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Author Topic: I swapped out my failed 129 for a 128…does the front diff need to be swapped?  (Read 1487 times)

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Offline Factory53

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  • Hoping to get my wagon back to a daily driver.
Hi everyone,

I went through all the threads and couldn’t see anything talking about what I have to sort out. So I apologize if I’m starting a topic that’s been sorted before.

I bought an 84 wagon and rebuilt the engine only to find out the VC in the np129 had failed. I was able to find an 86 parts car with an np128 non-vc just so I could get the car moving again.

I’m curious what my options are now to get my 4WD working again.

The original front diff in my 84 has a vacuum unit on it, but the 86 parts car that I took the 128 out of did not. Also, the 128 TC has one less vacuum line than the original 129 had.

Should I do the work to swap the 86 front diff and axle into my 84 or is there another option to make the vacuum set up work on the original front diff on the 84 with the 128 out of the 86?

I apologize if I’m not using the right names of parts. Just learning about all of this.

Hoping to find a solution to get all 4 wheels powered. Cheers!
« Last Edit: March 26, 2022, 10:06:43 AM by Factory53 »
1984 AMC Eagle Wagon Limited
1986 AMC Eagle Wagon (donor) - parted out and sold

Next up - Holley Sniper BBD swap - then I'll throw a Carter BBD smashing party

Offline Factory53

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  • Posts: 31
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  • Hoping to get my wagon back to a daily driver.
I apologize if this should have been posted to the 4WD channel.

I was too focused on the diff but it’s probably more a TC issue/conversation.
1984 AMC Eagle Wagon Limited
1986 AMC Eagle Wagon (donor) - parted out and sold

Next up - Holley Sniper BBD swap - then I'll throw a Carter BBD smashing party

Online Taylor

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I wouldn’t think anything else would need to be changed, unless there is a additional problem. Is everything else functioning as it should?
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1985 AMC Eagle Limited Wagon 🖖🏼🦅
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Offline rmick

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You can leave as is or change it to the simpler set up on the 86 to shift on the fly rather than stop and shift. http://amceaglesden.com/guide/Front_Axle_Lock
http://amceaglesden.com/guide/Shift_on_the_Fly_Vacuum_Set_Up
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Offline Factory53

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  • Posts: 31
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  • Hoping to get my wagon back to a daily driver.
I wouldn’t think anything else would need to be changed, unless there is a additional problem. Is everything else functioning as it should?

That's what I was thinking too. As far as additional problems goes...there could be. I need to spend more time testing vacuum and seeing if those vacuum motors or units on the TC and front diff are working.

But it sounds like I should be able to leave the 84 front diff alone and get it to work with the 86 TC that I've installed.

Cheers!
1984 AMC Eagle Wagon Limited
1986 AMC Eagle Wagon (donor) - parted out and sold

Next up - Holley Sniper BBD swap - then I'll throw a Carter BBD smashing party

Offline Factory53

  • Eagle
  • **
  • Posts: 31
  • Thumbs Up 3
  • Hoping to get my wagon back to a daily driver.
You can leave as is or change it to the simpler set up on the 86 to shift on the fly rather than stop and shift. http://amceaglesden.com/guide/Front_Axle_Lock
http://amceaglesden.com/guide/Shift_on_the_Fly_Vacuum_Set_Up

Thank you for this information Rmick. I'm going to share this with my brother who does the important wrenching for me. This gives me something to consider for sure.

Cheers!
1984 AMC Eagle Wagon Limited
1986 AMC Eagle Wagon (donor) - parted out and sold

Next up - Holley Sniper BBD swap - then I'll throw a Carter BBD smashing party

Offline Canoe

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You can leave as is or change it to the simpler set up on the 86 to shift on the fly rather than stop and shift. http://amceaglesden.com/guide/Front_Axle_Lock
http://amceaglesden.com/guide/Shift_on_the_Fly_Vacuum_Set_Up

Thank you for this information Rmick. I'm going to share this with my brother who does the important wrenching for me. This gives me something to consider for sure.

Cheers!
Very cheap "upgrade".
One less 'device' in the system to fail when you're on the road, and it's wonderfully convenient.

 

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