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  • June 26, 2022, 02:05:30 PM

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Author Topic: Disconnect vs non disconnect. and Right Rear axle problem.  (Read 599 times)

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Offline Paul Revere

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Disconnect vs non disconnect. and Right Rear axle problem.
« on: April 14, 2022, 09:47:59 PM »
Had a quick question that came up after reading a few topics on this board.

I have 2.35 gears in my wagon, it's a 1985 with shift on the fly. It was my understanding that you can't flat tow an eagle because the Axles and shafts are turning all the time unlike a jeep yj where the front tires are free to spin without turning the axle. That and lack of N on the TC means you have to pull the driveshafts. 

I keep seeing g people refer to a non disconnect vs a disconnect axle. does that mean some were equipped with a similar vacuum wheel disconnect like the YJ? or are people referring to something else.

I dont plan on changing my gears, my wagon is a highway machine so the mpg savings are paramount, I'm more looking at this from a breakdown perspective.
How can I tell which axle I have? and what will fit in each. is there a jeep/cj 2.35 carrier and gear combo still available that will fit.

I also keep seeing people mention the Right rear axle problem, can someone explain what that is? and how to do a preventative fix, or tell if someone's already fixed it. My eagle is going on a 12000 mile riadtrip. I dont want it to happen at the worst possible time.

Offline MIPS

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #1 on: April 15, 2022, 02:15:47 PM »
My information on this was that originally Eagles had permanent 4WD, then they added SelectDrive for economy which added actuators at the transfer case and the front diff. This is what they call a disconnect axle.




 Put a camera under the car you will see that in 2WD the front propeller shaft isn't spinning. The actuators are interlocked, so you have to stop the car and switch modes and let the diff engage/disengage before it will actuate the transfer case. I've found several actuators now from this era where the diff's actuator lightly seizes and it disables everything.
Then they switched to only one actuator at the transfer case so you could switch on the go but the front diff is always engaged.
I've had my vehicle towed several times (which isn't a proud thing to say) and even with the SelectDrive switched to 2WD they have to put dolly wheels under the rears because even if you leave the transmission in neutral and the TC disengaged there's a risk or ruining your viscous coupling.

Quote
I also keep seeing people mention the Right rear axle problem, can someone explain what that is? and how to do a preventative fix, or tell if someone's already fixed it. My eagle is going on a 12000 mile roadtrip. I don't want it to happen at the worst possible time.

You mean the axle snapping at the wheel hub?
I had that happen last year. AMC 35 axle shafts are now out of production and the only good and safe fix is to replace the axle entirely with a Dana 35, which isn't a cheap solution. If you have another AMC 35 available, steal the symmetrical axle shaft out of the drivers side and in theory, you are less likely to have the shaft snap again. I don't entirely trust this solution myself.
I still can't find an official bulletin, when it started happening or when it was remedied but it seems to be a combination of an incorrectly factory torqued axle nut and I don't know if I stripped my splines out before it broke away completely but the splines in the hub were really shallow. It felt like the hubs originally didn't have splines and when the shaft and hub were combined and torqued the hardened shaft would cut its own splines. I guess that works, but if you overtorque the nut you will stress the shaft in the hub and if the hub ever slips on the splines you'll introduce radial stress on the already stressed area.



I can't think of a lot you can do once the damage is done. You could try cutting a keyway to reinforce against the hub wandering in the splines and retorque the nut a little lower. If you just weld the hub to the shaft you can't reach the bearings or shaft retainer. If you are going to pop the hub off to inspect I guess inspect the splines, look for torque yielding on the first three inches of the shaft and any obvious cracks.

Edited: I just double checked and the shaft IS already keyed and it STILL sheared. Yeah. I can't recommend anything else. There's a reason Dana changed it.
« Last Edit: April 15, 2022, 03:01:09 PM by MIPS »

Offline Paul Revere

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #2 on: April 15, 2022, 08:11:27 PM »
Thanks for the info!
Since I have shift on the fly I have the non disconnect version. so it seems jeep carriers will fit that casting.

D35s are relatively common at least, real matter will be findi g one with 2.35 gears.

Offline Softbuster

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #3 on: May 08, 2022, 09:03:15 AM »
For the rear axle your best bet is to find a good used replacement shaft and hub from another AMC 15.
I doubt you will ever find a Dana 35 with 2.35 gears,  unless  the gear set from the AMC would swap over (not sure if anyone has ever looked into that)  AMC sold the tooling for The 15 to Dana to become the 35, so who knows!

sifting through the whole front axle info on here you can find out that the 1984 and up front axles use a standard Jeep carrier for the 2.35 gears and there is hardly any way around putting other gears in there without A. a ring gear spacer (which is a terrible idea on a front axle in full time 4wd flying down the road)
Or B. find a front axle with the 2.73 - 3.54 carrier which is unique to the eagle as far as anyone has found.
If you wish to dive into the subject of finding another source for front axle carriers to find out if its truly a one off from Dana or if there is another vehicle out there that uses them that they can be sourced from.  like Ranger/explorer Dakota/Durango  Were there any 4wd Areostars?  Or other oddball 4wd with the dana 30?   Have fun!

I know where there is some AMC 15 shaft/hub assemblies in eastern Pennsylvania, if you wish to travel.
Best bet is to put out wanted ads here, on the AMC forum and social media / craigslist.
1985 Eagle sedan rescue project

Offline Paul Revere

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #4 on: May 08, 2022, 04:11:28 PM »
For the rear axle your best bet is to find a good used replacement shaft and hub from another AMC 15.
I doubt you will ever find a Dana 35 with 2.35 gears,  unless  the gear set from the AMC would swap over (not sure if anyone has ever looked into that)  AMC sold the tooling for The 15 to Dana to become the 35, so who knows!

sifting through the whole front axle info on here you can find out that the 1984 and up front axles use a standard Jeep carrier for the 2.35 gears and there is hardly any way around putting other gears in there without A. a ring gear spacer (which is a terrible idea on a front axle in full time 4wd flying down the road)
Or B. find a front axle with the 2.73 - 3.54 carrier which is unique to the eagle as far as anyone has found.
If you wish to dive into the subject of finding another source for front axle carriers to find out if its truly a one off from Dana or if there is another vehicle out there that uses them that they can be sourced from.  like Ranger/explorer Dakota/Durango  Were there any 4wd Areostars?  Or other oddball 4wd with the dana 30?   Have fun!

I know where there is some AMC 15 shaft/hub assemblies in eastern Pennsylvania if you wish to travel.
Best bet is to put out wanted ads here, on the AMC forum and social media / craigslist.

I thought it went like this from what I've read on here
1. the 1980-1984 with the 2.35 d30 Casting was different than the 1980-1984 with the higher gear ratios, therefore if you have 2.35 in those years you need a whole front axle from a higher gear eagle to get any gear above 2.35.
2. 1985-1988 used the same d30 casting regardless of gearing so you can swap in a higher gear ratio with a new jeep carrier into it, because they got rid of the vacuum motor assembly to enable shift on the fly, so all the axles were the same non-disconnect axle.

THanks for the tip on the Axle shafts! I can always get them shipped if I need.

Offline Softbuster

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #5 on: May 08, 2022, 08:44:43 PM »
From what i understand (there's a lot of info to read through)
80-81 did not offer the 2.35 gear ratio, lowest was 2.73.  so lower (higher numerically) can be swapped in.
82-84 year is debatable
85-88 2.35 was standard and the housing was changed to use the standard carrier from 80-81 for the 2.35 ratio (which is also a standard jeep D30 carrier)
The carrier that is a "one off Eagle product"  is the 85-88 2.73 - 3.54 gear ratio carrier.
So if you have a front axle with 2.73 and up gear ratio you can swap in the standard 3.54 or 3.08 ratio that a lot of jeep axles came with to match up with a jeep Dana 35 rear axle.
Any Eagle front axle with the 2.35 ratio is a problem to swap gears into without changes.
I would only use a ring gear spacer if it was never going to see road use again.
1985 Eagle sedan rescue project

Offline Paul Revere

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #6 on: May 09, 2022, 08:44:25 PM »
From what i understand (there's a lot of info to read through)
80-81 did not offer the 2.35 gear ratio, lowest was 2.73.  so lower (higher numerically) can be swapped in.
82-84 year is debatable
85-88 2.35 was standard and the housing was changed to use the standard carrier from 80-81 for the 2.35 ratio (which is also a standard jeep D30 carrier)
The carrier that is a "one off Eagle product"  is the 85-88 2.73 - 3.54 gear ratio carrier.
So if you have a front axle with 2.73 and up gear ratio you can swap in the standard 3.54 or 3.08 ratio that a lot of jeep axles came with to match up with a jeep Dana 35 rear axle.
Any Eagle front axle with the 2.35 ratio is a problem to swap gears into without changes.
I would only use a ring gear spacer if it was never going to see road use again.

See I think the casting carrier and gear are unique eagle only items if you have 2.35
That's why you need a whole new everything to swap to anything else. the shorter gears and carrier are interchangeable with jeep parts and therefore if you need to swap you can buy aftermarket stuff to fit in the housing.
I think in 85 they made one housing to fit all gears when they swapped to the non disconnect setup. so in theory you can swap in an aftermarket carrier and gear with shorter gears into the housing if you had 2.35 as well as shorter gears stock.

Offline Canoe

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #7 on: May 10, 2022, 11:39:51 AM »
...
85-88 2.35 was standard and the housing was changed to use the standard carrier from 80-81 for the 2.35 ratio (which is also a standard jeep D30 carrier)
The carrier that is a "one off Eagle product"  is the 85-88 2.73 - 3.54 gear ratio carrier.
So if you have a front axle with 2.73 and up gear ratio you can swap in the standard 3.54 or 3.08 ratio that a lot of jeep axles came with to match up with a jeep Dana 35 rear axle...
Curious. How does my '86 diff with tags that claim 2.72 fit in.

Offline Softbuster

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #8 on: May 14, 2022, 06:28:42 AM »
The housing was changed to fit the 2.35 gear ratio, they set the pinion farther away from the carrier and thus were able to use  the standard carrier for the 2.35 with that huge pinion gear.   So going to a lower (higher numerically) ratio requires a unique carrier ... in all the info on here i have not seen anyone try a D30 carrier for 5.13 or lower ratios. (does such a thing exist without a ring gear spacer?)

Canoe:  from how i understand the info, your axle should accept the 3.08 or 3.54 gear ratio because of the carrier in it.
             EDIT;  ..... unless there IS a difference between the 2.73 and 2.72, are you sure its 2.72?
« Last Edit: May 14, 2022, 06:33:40 AM by Softbuster »
1985 Eagle sedan rescue project

Offline Canoe

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #9 on: May 14, 2022, 01:09:06 PM »
... Canoe:  from how i understand the info, your axle should accept the 3.08 or 3.54 gear ratio because of the carrier in it.
             EDIT;  ..... unless there IS a difference between the 2.73 and 2.72, are you sure its 2.72?
Tag says 2.72... I guess emphasis should be on 'says'.

Offline Softbuster

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #10 on: May 14, 2022, 08:54:28 PM »
Canoe; 
So i figured out that the 2.73 number is wrong.  Everything listed is 2.72 so i'm not sure where the 2.73 is coming from, maybe the rear axle number?  Like with Jeeps the 3.54 is sometimes listed as 3.55 for some reason even though the tag says 3.54.
My bad if i caused any confusion, you should be fine swapping in 3.08 or 3.54


Paul Revere;  Sorry for hijacking your thread
1985 Eagle sedan rescue project

Offline Paul Revere

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Re: Disconnect vs non disconnect. and Right Rear axle problem.
« Reply #11 on: May 16, 2022, 05:43:12 PM »
Canoe; 
So i figured out that the 2.73 number is wrong.  Everything listed is 2.72 so i'm not sure where the 2.73 is coming from, maybe the rear axle number?  Like with Jeeps the 3.54 is sometimes listed as 3.55 for some reason even though the tag says 3.54.
My bad if i caused any confusion, you should be fine swapping in 3.08 or 3.54


Paul Revere;  Sorry for hijacking your thread

No apologies nessicary, your previous post about the housing being changed for all of them to fit 2.35 gears makes sense and now I understand why the carriers for higher gear eagles are needed to do any kind of swap. :)

 

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