Dana 44, What Changed?

I bought a rear Dana 44 to replace the original in my 55 CJ 5 which was destroyed by rust internally.The only difference with the new axle is that it had thicker and fewer splines to engage the diff. Same gearing. I replaced the bearings and seals just as the minimal thing to do before bolting this one up, The seals and bearings I bought were dimensional matches to what was previously in use.

But now I've run into a little weirdness. When I slide the axles in there's not enough clearance for them to go all the way in. When I push one all the way in, l the other one pops out about a quarter inch further than relatively flush, which was how it was before.

Which dumb thing am I forgetting?

 

The spacer block thingy thing in the differential is probably causing this .it’s a little block with a pin on each side that slides it to the hole on the end of the axle shafts it sets the preload on your wheel bearings.

 

There is a shimming procedure outlined in the FSM, sounds like you need to perform that. The shims are installed at the outer tubes where the bearing and retainer are.

 

Sorry, I probably wasn't clear. The axles in this have 10 splines, the same axles that came out went back in with new bearings. The old, full axle assembly was a higher spline count and the whole, ruined unit has been set aside. No part of that is being re-used here.

 

I'm looking at the procedure now, thanks. Is it normal to shim .100 per side?

 

Your ruined axle likely had the stronger 19 spline axles. The axle housings should be interchangable, but you need the spider gear’s spline count to match the axle you are using. Have you tried to mount up the bearing retainer and backing plate on one side, then see if the bearing still protrudes too far on the other side?
Where in central Florida are you? I’ll be up in West Palm Wed. Or Thur..
-Donny

 

Thanks, I'm not interchanging any parts. The same parts that came out for a new seal and bearing are the ones that went back in.
I haven't done anything with the plate, I'm just pushing one side in flush with a finger and the other protrudes out. It's a mystery for sure, at least to me.

I'm in Cocoa, that's about 2 hours up 95 from WPB.

 

Jeep Peep may be right about the spacer block causing this, but it is not what sets preload on the bearings, that is done with the shims under the retainer plate on the axle.

 

I stand corrected thanks. I went through this once before and that was the cause.

 

Your going to need a shim pack kit (to be able to add shims if necessary since you have new bearing/races) if you don't already have one, with one axle pushed all the way install race and temporarily loosely install the retainer on that side. with two bolts, then do the same thing on the opposite side to establish approx amount of shim pack for axle housing. Measure gap on the pushed out side and install 1/2 of that dimension of shims to that side. then go back to opposite side axle and remove the two bolts and retainer to be able to add the rest of the shim pack dimension. All were trying to do is get approx half of the shims on each side btween the housing and the retainer. then the manual calls out the end gap clearance I think it's close to .006" and add or subtract shims to get that dimension. Hope I didn't make this too confusing but that's how I do it to end up with a closely centered axles for the brake drums to have the same drum the backing plate clearance. If you stack up all the shims on one side (which can be done) it will cause a clearance difference that may cause some problems with OCD owners.

 

This can't be right;

 

...or maybe it is. I can look down through the tubes and see that there is a spacer in there with a dark spot in the direct center of it, so I guess it's oriented right. It's just sort of hard to see and there, maybe there's a piece of garbage in there that's keeping the shaft from going all the way in on one side or the other. The only thing I can think is that I'll have to pull the diff out to tell for sure.

 

If I do take the differential out should I expect to be able to use the same shims, or at least the same cumulative thickness of shims and put it back in without any hassles?

 

I wouldn't jump right into removing the differential, probably nothing wrong with it.

Those axles didn't grow longer while you had them out, and there are only three things I can think of that could cause what you are running into.

Check these.

1) Debris, or even grease inside the carrier hub might keep one of the axles from making full contact with the spacer block.
2) Bearings not fully seated. The bearings should be pressed on so that there is no space between the center race and the ring on the axle.
3) Wrong bearings. I have never heard of it, but there sure is a lot of imported crap out there nowadays. Check to see if you somehow got bearings that are thicker than the ones you removed. If you no longer have the old bearings to compare to, part number and brand of the new bearings would be best, but if you can't determine that measure what you have and someone will be able to tell if they are correct.

Get this figured out before you start tearing down your rear end.

Folks on this forum will be able to help you diagnose the problem, and it is probably something easy to fix.

Then comes reassembly.

Since I don't know how experienced you are with these old tapered axle Dana rear ends, a word of caution about installing the hubs.

A far too common mistake is made by installing the key before the hub. If you do that, 9 times out of 10 the key will be pushed ahead of the hub when you tighten the nut, it will ramp up in the slot and cause the hub to split when you torque it to spec. This will cause the hub to fail which can be a dangerous event.

Put the hub on first, align the key ways, tap in the key until it is flush with the end of the hub, then when you put on the washer and nut you can tighten it to specified torque and the key and hub will be pushed as a unit. Torque to 150 lbs, if the castle nut doesn't line up a slot with the hole for the cotter pin, tighten a little more until it does, DO NOT loosen it to align the pin.

 

So yeah, it ends up that it was fine. After shimming the ends it took up the space in the middle and everything seems good. In the end I can at least say I err on the side of caution and don't force things.

I suppose if I had someone around who could point out the dumb sh*t I do in person that would help, but if my biggest problem is that I outlived my friends I'm going to live with that. No pun intended.

EOF.