Dana 44

My old 87XJ had a Dana 44 and I had to replace the seals and bearings.
Best I can remember a plate prevents the shaft from coming out of the axle.
I seem to remember that the plate acts on the seal and that seal was nothing special.
I must be making a mistake considering that everybody thinks that the 44 is strong. What keeps the shaft in place?

falcon556 said:

My old 87XJ had a Dana 44 and I had to replace the seals and bearings.
Best I can remember a plate prevents the shaft from coming out of the axle.
I seem to remember that the plate acts on the seal and that seal was nothing special.
I must be making a mistake considering that everybody thinks that the 44 is strong. What keeps the shaft in place?

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All Semi Floating, non clip axles have a axle shaft retainer plate. How does that have anything to do with the strength? You think the shaft just holds itself in?

91 Jeep Project said:

All Semi Floating, non clip axles have a axle shaft retainer plate. How does that have anything to do with the strength? You think the shaft just holds itself in?

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Every time you make a turn or drive on uneven ground a shaft tries to get out.
It seems to me that what keeps it in place is the plate pushing on the seal and the seal pushing against the bearing.
In other words the seal holds the shaft in. I seem to remember that the seal is nothing special, I keep thinking I'm missing something.

falcon556 said:

Every time you make a turn or drive on uneven ground a shaft tries to get out.
It seems to me that what keeps it in place is the plate pushing on the seal and the seal pushing against the bearing.
In other words the seal holds the shaft in. I seem to remember that the seal is nothing special, I keep thinking I'm missing something.

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The seal keeps the diff fluid from leaking out the side of the axle....

The bearing is press fit onto the shaft, and it is that press fit working (indirectly) against the strength of the retainer plate that holds everything together.

However, the "strength" of an axle isn't so much measured against how it retains its shafts (unless you're dealing with a C-clip - where you're stuck. It's entirely possible to make a thicker/stronger/harder retainer plate, but the C-clip thickness is fixed,) it's measured against the strength of the ring & pinion gear teeth - that's what usually lets go when an axle grenades.

The Dana 44 is a fairly common axle that saw use in full-size trucks (1/2-ton and 3/4-ton, I think. Maybe some 1-ton trucks as well...) and I think it was occasionally available in a Dual Rear Wheel (DRW, or "dually") configuration as well.

Is the D44 as strong as it gets? Hell no! You can always go with a D60, D70, D80 - I've also heard that a Ford 9" is stronger than a D44 (and there are advantages to the Ford 9" - I just happen to prefer Danas for some odd reason. I've build both.) The ChryCo 8.75" and 9.25" are also options - you could also get silly and do the ChryCo 10.25" or even go with Rockwell 2.5-tons, if you've got the dosh to spare (could you spare a little my way?)

However, the Dana 44 has one main advantage - it's readily available, and the racers tend to prefer the Ford 9" (which causes an artificial shortage from time to time.) Parts for the Dana are also readily available, which helps to make it ideal for swaps.

All else being equal, I'd still take a D44 any day - hands down! - over the D30 and D35 we're saddled with right now...

5-90

I started to take apart my D44 also and noticed what falcon is noticing. I've serviced three other cars I have with similar axle retention. A 69 Pontiac, 77 Celica, and a 92 Toyota Pickup. Like the D44 they all use a retainer plate to keep the axle in.

However all the other three use unit bearings where the retainer plate acts against the OUTER race of the bearing. The outer race of the bearing is then locked into place and the axle is kept in place by the press fit into the inner race of the bearing and the pressed-on-retainer aids retention.

The D44 differs in that the bearing is a conical bearing which can handle much higher side forces in one axial direction and none in the other. So to keep the axle from popping out, the retainer plate must act against the seal which then acts against the inner race of the conical bearing. If the side forces exceed that which the seal can handle and as such the seal compresses, then there will be play allowing the bearing to come apart slightly and pop back in as the vehicle turns left to right visa versa. If this is possible, I don't know, but I was much surprised to see the the D44 designed this way.

I've heard that there are unit bearings that fit in the D44 but I'm not sure if this is better that the conical bearing. My intuition tells me its better but what does everyone else think?

SuperRA said:

I started to take apart my D44 also and noticed what falcon is noticing. I've serviced three other cars I have with similar axle retention. A 69 Pontiac, 77 Celica, and a 92 Toyota Pickup. Like the D44 they all use a retainer plate to keep the axle in.

However all the other three use unit bearings where the retainer plate acts against the OUTER race of the bearing. The outer race of the bearing is then locked into place and the axle is kept in place by the press fit into the inner race of the bearing and the pressed-on-retainer aids retention.

The D44 differs in that the bearing is a conical bearing which can handle much higher side forces in one axial direction and none in the other. So to keep the axle from popping out, the retainer plate must act against the seal which then acts against the inner race of the conical bearing. If the side forces exceed that which the seal can handle and as such the seal compresses, then there will be play allowing the bearing to come apart slightly and pop back in as the vehicle turns left to right visa versa. If this is possible, I don't know, but I was much surprised to see the the D44 designed this way.

I've heard that there are unit bearings that fit in the D44 but I'm not sure if this is better that the conical bearing. My intuition tells me its better but what does everyone else think?

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I recently bought and disassembled a D44. What I found is that the seal is made with extra strong sidewalls that are capable of doing the job. The retainer pushes against the seal and preloads the bearing.
Basically it is designed better than I originally thought.
The seal outer portion is solid and pushes straight on the bearing. Unlike other seals of this type that have a thin outer cylinder, this baby is beefy.
No problem.

Dana 44 rear ends are sufficient to the needs of a light XJ. The Ford 9 inch is absolutely superior as a rear end for racing applications, or if purchased inexpensively, for any application, even an XJ.

I have built hot rods with both Dana 60's and Ford 9 inch rear ends, and both work well. I have restored 2 ton dually Ford trucks with humongous rear ends. I prefer the Dana 44 in XJ's and like the older 44's over newer, smaller rear ends. They are very sturdy for the application. :rof:

Yea, I have no doubt it's plenty strong. It just bother's me why they decided to engineer it that way. You'd think there'd be more friction that way with no thrust bearing or anything. Anyhow I find it funny that the beefiest bearing outo of the 4 different axles I have is for the smallest car, the celica?!? That thing is probably about 2" wide!

falcon556 said:

I recently bought and disassembled a D44. What I found is that the seal is made with extra strong sidewalls that are capable of doing the job. The retainer pushes against the seal and preloads the bearing.
Basically it is designed better than I originally thought.
The seal outer portion is solid and pushes straight on the bearing. Unlike other seals of this type that have a thin outer cylinder, this baby is beefy.
No problem.

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