AMC20 Death

[YJeXtreme]

Well about 1 1/2wk ago the drivers axle bearing took a on my CJ7... they had maybe 2500 miles on them. Instead of sinking more $$ into the M20 thats been fully rebuilt, i’ll be building a custom 9” Ford rear.

Anyone in/near VA interested in M20 rear with 4.56 gears (2500-ish miles) & spartan locker (500-ish miles) has unknown branded 1 piece shafts, setup for SOA & has Barnes 4wd anti-wrap bar brackets...

 

[gert]

Dang you had some good money tied up in it


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[jp360cj]

Unless the housing is bent, either the bearings weren't packed good or had too much preload. The last couple ones I've done, I drilled a hole in the inner seal to let some gear oil get to the bearing.

Something to think about on the rear....Sounds like you'll be spending some coin on that rear. Since you are already SOA, I would consider going a little wider than stock. I went with an early Bronco 9" rear that's 58" WMS and wouldn't mind it being a little bit wider. If you want to be able to use off the shelf shafts, you could probably use 2 long side EB shafts and get around 60" (which is YJ/TJ width). Mine is 28 spline, but wish it was 31 spline (stronger and better locker selection).

Of course, the extra width means you need to do something about the front axle. Spacers could get you by, assuming it's WT.

 

[Kane]

Unless the housing is bent, either the bearings weren't packed good or had too much preload. The last couple ones I've done, I drilled a hole in the inner seal to let some gear oil get to the bearing.

Some aftermarket 1 piece axles use Set9 roller bearings and do not need a preload. My Moser axles had them. The downfall is they are not a strong as tapered bearings but they are easier to set up.

 

[YJeXtreme]

Unless the housing is bent, either the bearings weren't packed good or had too much preload. The last couple ones I've done, I drilled a hole in the inner seal to let some gear oil get to the bearing.

Something to think about on the rear....Sounds like you'll be spending some coin on that rear. Since you are already SOA, I would consider going a little wider than stock. I went with an early Bronco 9" rear that's 58" WMS and wouldn't mind it being a little bit wider. If you want to be able to use off the shelf shafts, you could probably use 2 long side EB shafts and get around 60" (which is YJ/TJ width). Mine is 28 spline, but wish it was 31 spline (stronger and better locker selection).

Of course, the extra width means you need to do something about the front axle. Spacers could get you by, assuming it's WT.

The seals allowed plenty of gear oil to seep by. The shafts really should have been replaced when I did the regear.

The problem is, with the amount of heat that was generated when bearing failed, it’s possible housing end was warped. I’ve come across this on 9” housings where someone ran them dry & overheated the bearings. (Actually where one of my spare 9” housings came from)

Since I wheel my CJ, and drive regularly, it makes more sense to move to 9”, which i’ll build as 31 spline & chromoly shafts.

I’ll be doing the narrowing, debated on going EB width, but not a fan of running spacers. Since I already purchased shallow backspaced wheels(upgraded steering required either 17”+ wheels or shallow backspaced wheels), i’ll likely stay CJ width.

 

[Lumpy Grits]

You'll love the 9".
Been run'n a Currie built 9" for over 27 yrs in mine.
Just the size upgrade in brakes, makes the switch worth it.
LG

 

[YJeXtreme]

You'll love the 9".

Been run'n a Currie built 9" for over 27 yrs in mine.

Just the size upgrade in brakes, makes the switch worth it.

LG

I’ve been building Fords for years & jeeps for over 10... most my jeeps get 9” rear unless going full rock-crawler.

I keep a lot of 9” parts in stock in my storage, have disc brackets too.

 

[YJeXtreme]

Have new Alloy USA bearing kits en route... going to temp fix the M20 while I build the 9”

 

[YJeXtreme]

Been awhile... rear still makes some crappy noises... so I’ve kept jeep parked. Began work on below... i’ll soon have an M20 for sale... 4.56 gears have less than 2k miles, locker has less than 500 miles, Riddler Cast Iron cover...











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[gert]

Sweet that Ford 9 will definitely get the job done


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[YJeXtreme]

Sweet that Ford 9 will definitely get the job done


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For sure. The backbrace is overkill, but O’ve bent 1 stock full-width 9” before in a YJ on 38s, so I’d rather go beefy & never worry again


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