Closed knuckle D44HD strength

[montana_hiboy]

How stout is the closed knuckle D44HD when running 35" and up tires? what's the weak link, axle shafts? u-joints? spindle bolts? all the above?

i've heard the spindle bolts have a nasty habit of coming loose on the closed knuckle 44 and possibly shearing off when running oversized tires i.e. 35" and up, can anyone either confirm or deny this suspicion? thanks.

[67ford]

I broke mine with 35s, but then again I break everything. So take that with a grain of salt i guess. Depends how hard you are on stuff.

[averagef250]

The HD Ford closed knuckle is one of the stronger 44's. The knuckles themselves are stout, more beef than the lighter versions for sure. They use the small 6 bolt spindle pattern just like all the later GM, dodge, IH axles. The open knuckle Fords switched to the stronger big 5 bolt pattern.

Just like any other 44 the parts you're going to break axles/joints, spiders and lockouts. The old spicer external lockouts are pretty tough if they're working. The pot metal warn ones are sh!t, but they do save your axleshafts I guess. Maybe just bolt the Warn ones with plastic bolts and they'll spit the bolts out before the hubs come apart?

[montana_hiboy]

Other than the obvious advantages of an open knuckle axle i.e. disc brakes, high pinion (if 78/79) is the stronger 5 bolt spindle pattern on its own enough to warrant an axle swap if a guy's running 35's?

or is the strength difference between the earlier 6 bolt spindle and later 5 bolt spindle negligable for typical street use?

[averagef250]

negligable.

GM trucks always had the little 6 spindle pattern on everything besides the 60 front axles. They don't break spindles at an alarming rate.

Comes down to how much you hammer on stuff. If it's a toy and you plan to break it that's one thing. If the truck helps earn your living you're not going to do anything that will break a Dana 44. Make sure it's in good shape before you lock the hubs and the front will be fine.

[montana_hiboy]

Thanks, that's what i needed to know

out of curiosity what gives the later 5 bolt spindle more strength than the earlier 6 bolt spindle? is it simply bolt diameter? and/or the way the bolts fasten to the spindle/knuckle assembly?

[montana_hiboy]

I got a chance to see exactly what you mean Dustin, i was out at the junk yard today and had the luxury of finding both a closed and open knuckle axle torn down on a couple of highboys.

i didn't have a tape measure with me but the closed knuckle 6 hole spindle bolts looked to be 3/8" on a 5" bolt pattern, the bolts went through the spindle flange and threaded into the knuckle, no nuts.

the open knuckle 5 hole spindle bolts looked to be 7/16" on a 6" bolt pattern, the bolts went through the back of the knuckle into the spindle and fastened with nuts on the spindle flange.

i was kinda surprised how "weaker" the closed knuckle spindle looked when compared to the open knuckle spindle, not the spindle itself but the method of fastening it to the knuckle.

but i know there's plenty of guys out there that run 35's on their '67-'75 closed knuckle highboys without issue so the spindle attachment must not be as weak as it appears.

[FORD-F250-4x4-1972]

I got a chance to see exactly what you mean Dustin, i was out at the junk yard today and had the luxury of finding both a closed and open knuckle axle torn down on a couple of highboys.

i didn't have a tape measure with me but the closed knuckle 6 hole spindle bolts looked to be 3/8" on a 5" bolt pattern, the bolts went through the spindle flange and threaded into the knuckle, no nuts.

the open knuckle 5 hole spindle bolts looked to be 7/16" on a 6" bolt pattern, the bolts went through the back of the knuckle into the spindle and fastened with nuts on the spindle flange.

i was kinda surprised how "weaker" the closed knuckle spindle looked when compared to the open knuckle spindle, not the spindle itself but the method of fastening it to the knuckle.

but i know there's plenty of guys out there that run 35's on their '67-'75 closed knuckle highboys without issue so the spindle attachment must not be as weak as it appears.

hi there i am running 44 inch ground hawgs tires on my 1972 F-250 4x4 3/4 ton truck with no front end problems at all

[1971ford]

37" Goodyear Military OZ's (HEAVY tires)
1000lb Cummins 6bt
Cranked up Cummins 6bt torque
No pavement princess.

100% stock 44hd. No problems at all so far! Although, open diff's are a joke, and I wouldn't dare lock this 44. Being open diff is why it's still alive i'm sure.
I'm always the one with the camera so this is sadly one of the only pictures I have of it on a trail. But It does work its way over rocks, and through trails!
It has been bounced HARD up front as well.

[montana_hiboy]

^^^Thanks guys, that's reassuring to hear, i guess i was sweating it for nothing, i've ran stock sized 235/85/16's on this truck forever and i wasn't sure how well the the old closed knuckle HD44 would hold up to 35's, looks like i have nothing to be concerned about after all.

[averagef250]

Something to consider too is almost nobody who breaks a Dana 44 front axle took it apart, replaced everything worn out and put it back together right. To often it breaks because parts inside were totally worn out from lack of maintenance. When knuckle U-joints are sloppy or the grease inside them is all dried up they will come apart when you put power through them. The joint body gets a tiny bit of slop in the caps, this gives leverage to spread the ears on the shafts apart and you have a big mess.

poorly maintained front axles break almost too easy. Nice, tight ones are pretty tough.

[robertbruce]

I reckon the closed knuckle is plenty strong.... when you read about its design closed knuckle oare held together more by force and friction than by bolts and balls... They are high maintence but along with drum brakes checking them over is quick.. Just make sure your trunnion caps are not loose!

Something to consider too is almost nobody who breaks a Dana 44 front axle took it apart,

I did. Yep... pulled it all down, replaced lots, put it all back together then promptly went out and broke it!. Both the axle AND the knuckle...hehehe...

The knuckle I had overtightened, they are tricky to do up....took a while to find a replacement. All replacement are worn one way or the other and usually require a spruce at a engy shop... dont put jeep knuckles on it...
The axle was on a 30degree incline, half a lock on the steer, BOTH diffs locked and giving it to it with 33's jaggin on loose dusty ground... yer yer yer, striking a pose for the quad riders - im my coaster bus.... hehehe

just out of interesst - what size brake drums do you have?

[1971ford]

I guess I'll add that my front axle is very poorly maintained
I've never pulled it apart (Exception being hubs), and the front pinion seal is leaking real bad. Also, it's not leaking oil, it's leaking water. Has been for months. It must be full of water. I'll fix the pinion seal, drain and put fresh oil in, but i still won't rebuild it at all.
I need to break it eventually so i have an excuse for a Dana 60..

[adrianspeeder]

Ran mine for a year daily drivin' and playin' on the weekend with 35s no problems.

Adrianspeeder