Jeep rear-end tutorial

[SuperGas61]

Hey, everyone...I know a lot of people (myself included) have contemplated or are contemplating a rear-end swap for their old Mopar car or truck, and I know that Jeep rear-ends are often mentioned as replacements, so I just wanted to share this short YouTube video, which is a great little tutorial on the various Jeep rear ends available over the years:

 

 

Gary

[Loren]

Speaking of only the three axles mentioned in the video, all are integral housing types. That is, if you want to change ratios you either pull the entire axle or you do the work on a lift. If you have a lift and the skills required that's fine. If you don't have one or the other you'll want to pull the entire axle.

 

Of the three the Dana 44 is the most desirable. However, its design for some folks is a step backwards from the stock Plymouth axle.

Your Plymouth has a removable Differential Carrier (most likely a 3.73 ratio confirmable by looking at the area under the fill plug where the ratio is stamped) which means if you want to change ratios or you need to change a bearing, you do not have to remove the entire axle, you simply remove the Differential Carrier. This design is why the Ford 9 inch and the Chrysler 8.75 axles are favored over the Dana 44. The stock Plymouth uses all standard Timkin Tapered Roller Bearings so if you need a bearing you can go to any bearing supply or your favorite Mopar parts supplier.

Plymouth did not use the dreaded C-clips in the stock axle. The axles are retained by the out board bearing and they rumble a lot before they fail. I've had Dana 44 axles leave the vehicle with the wheel attached. Ford 9 inch and Dana 44 use a double row ball bearing and when they fail the wheel takes off. Those outer bearings on those axles are a pain to replace, where as the stock Plymouth is much easier.

 

The only draw back to the stock axle are the keyed tapered hubs. If you have access to a good heavy puller, they are not problem at all. The cost of a good puller is less than replacing the rear axle.

For my money there's not much of a case for changing the stock Plymouth axle. They wear out like everything else, but they rarely break (I've never seen only break). So for the money vs benefit of changing an axle I'd rather put my money somewhere else, like an Overdrive transmission.

Just sayn'

[Sniper]

The stock axle has stock brakes and those suck whereas the Jeep axles can be had with modern self energizing drum brakes or discs if that floats your boat.  It is not a problem to work on a integral housing axle, BTDT, without a lift but in either case a lift is nice.  One could argue that working on a integral housing axle is easier than wrasslin' the stock center section out of the stock axle housing.  Weight and all.  Not to mention your choice of gear ratios for the stock axle are severely limited.     

 

The reason the drop out center sections like the 9" and the 8.75 is the easy of swapping in a new ratio at the track, nothing more, nothing less.  there are many racers that use the Dana 60 and that is also a integral housing axle.

 

Both have their pluses and minuses, you just need an informed decision is all. 

[Dave72dt]

I've done integrals and carrier style on the ground, in the vehicle and both styles require the axle shafts being removed.  Neither require them to come all the way out but you have to get them at least out of the carrier.  C clip axles don't take any longer to get out than  unbolting backing plates.  Racing with an integral I'd probably have a complete axle standing by.

Edited November 19, 2021 by Dave72dt
added info

[Sniper]

I think Loren means the entire axle assembly not the axle shafts, at least that is how I read it.

 

C clips have the benefit of not having to pull the brakes off though.

 

[Dave72dt]

Guess I need to clarify and say "axle shaft".  I'll go back and edit.

[Loren]

If one has to have Bendix style brakes it would not take much to adapt the Bendix backing plate to the stock rear end then you could have your choice of 10x2, 11x2 or 12x2 inch Mopar drums. It would take a really sharp eye to notice the difference.

One might even take a look at when Chrysler switched over to the Bendix style and you might find out they will bolt right on.

I am not saying they do but I doubt Chrysler changed enough that they couldn't be made to work.

 

Common ratios available for the stock axle are 3.54, 3.73, 3.9, 4.1, if you find you need something outside of that range, then you might want to change the rear axle. However, my choice would always remain with the separate Differential Carrier type such as the 1957< Chrysler 8.75 or Ford 9 inch.

I am getting too old to wrestle with complete rear axles or setting up ring & pinions under the car.

I have the tools for Dana 44s and have done many. I just don't care to do one under the car or truck anymore. 

The stock axle was/is really well designed for its day.

The 1957< Chrysler 8.75 is the logical evolution of that design sized up for more power and torque.

That would be my first choice, but because they have such a good reputation they command a hefty price. You can sure afford a lot of stock axle parts for those prices.

As i said before, I'd be spending my time and money on other things with a greater return on investment.

But then your mileage may vary and it is of course your car and your choice.

 

I used to get in arguments with my Dad about "Needs" vs "Wants." He hated it when I told him "You don't need that to go faster, spend your money elsewhere." He always got what he wanted but when it came time to race (the Dry Lakes) he always drove cars I built, because his stuff was never ready.

I learned my lesson years ago that engineering projects rarely work right the first time. Better to use proven stuff than re-invent the wheel. If it bolts right on then it may work well first try. On rear axles: when you see a car crabbing down the road, the cause is usually the rear axle is out of alignment. If you never take it out, you'll never generate such a problem.

Just sayn'