Direct quote from High Perfrmance Pontiac magazine, December 1984........


"Available in open or true positraction designs (as opposed to the Eaton Locker), this rear is stronger than the 26-spline Chevy version which has a 7 5/8-inch ring gear, and is even stronger the the highly touted Dana 44 axle. The new B-W is the only axle on the new generation F-body to stand up to Pontiac's Woodward test schedule.

What's the Woodward Schedule? That's where they launch the car by sidestepping the clutch at 4000+ rpm and powershifting through every gear at the redline. So far, Pontiac has run about 30 of these axles through 200 Woodward test without a single failure of any axle component. Even the Danas broke in this test. Elimination of C-clips in the Borg-Warner and the use of tapered roller bearings at the wheels are additional strong points of the design."

 

I wonder what part of the Dana broke? The 9 bolt has a 4 pinion Borg Warner limited slip differential and I think the Dana only has 2 pinion gears. That might be where the Dana broke. I can't see the ring & pinion being stronger in the 9 bolt. The Dana has a 8 1/2 inch ring gear where the 9 blt only has a 7 3/4 inch ring gear.

 

It usually all comes down to traction/bite for the app, in general.

If its skating on ice your not gonna break allot of parts.

But stick 800lbs of sand in the hatch and dump that clutch at 4000

You will find all sort of "weak" parts.............

 

True....But the point was, that the M78 surived GMs standardized tests, the Dana 44 didn't.

No "Well, the M78 was probably on ice & the Dana 44 had slicks on a dragstrip launch pad." bs crap.

Equal tests........1 survived, 1 didn't.

 

IMO a large contributor to the strength apart from the 4 spider gears is the small yet bulky carrier, the dana and eaton units with their wet clutch packs are big open housings with large windows and often sharp edges and casting defects (smoothing and polishing those does help) and they are drilled for a center pin. It's very common to crack these from the pin outward or crack one of the windows.

 

thats great that a 1984 mag/gm test said that, but find a real world example of this. 9 bolts are only MODERATELY stronger than a 7.5"/7.65" ten bolt, thats an accepted fact, and D44 were used as warranty replacements by GM for 9/10 bolts that broke, and they were used by SLP in the firehawks.

so unless your going to say that SLP, and GM are incorrect in using the D44 as a stronger replacement for 9/10 bolts, because you found it in a magazine from 1984 (well before the SLP firehawks, so they would have heard of this "woodward test") you may want to reconsider what you believe as fact.

Also, having talked to numerous people running D44's in their third gens, as well as a very reputable axle shop (pyle bro's in houston), i have never heard of breakage that wasn't from a WELL above stock output motor unless there was a part defect. ESC here on TGO has been running a D44 at 300-500+hp power levels for years, and has never had a problem with his D44. Just putting my 10 bolt internals next to my D44 internals, there's no way the minimal size increase in size that the 9 bolt has over the ten bolt can come close to being as strong as a D44

 

Just because some dumb-*** who writes magazine articles says the 9-bolt is stronger than a Dana 44, does not mean its true. If it was, you would see people making conversion kits to take their weak Dana 44 out of their Corvettes and Vipers, and put a 9-bolt in them. One other point, how come all the Camaro/Mustang Challenge racers look for Dana 44's and won't run a 9-bolt. I have had 10-bolts, 9-bolts, Dana 44, 12-bolts, and Ford 9-inch, in my Camaros. Also, if anybody wants one of those "weak" Dana 44's, I have a spare one that is fresh with an aluminum cover and 91-92 PBR brakes on it.
Jerry

 

I knew the warranty issue would come up & I have a very real, possible arguement for that.....

In-house parts, not Australia imported parts. Lets ignore ANY strength issues. Lets just look at the money side for GM, which is what any LARGE portion of what any corporation looks at. Is is cheaper to use an in-house unit vs an "imported" unit?

Not to mention, there was only what.....23 Firehawks built? Were they even covered by warranties, in racing applications? No. So who cares if something on 1 of the 23 broke? Not like GM was gonna be out any money on warranty coverage for that car anyways!

 

I guess the engineers at GM are dumba$$es too, in believing their own test results.

You don't hafta post as royal *****. If you don't believe GMs test results, thats fine. Just don't hafta post up & be a real a$$ about it.

 

Please post a link to them.

Jerry

 

I hand typed what the magazine article said. I'm no GM Engineer who is privy to 20+ year old records.

 

Bingo. I dont care what some half assed article says. In the real world, Dana 44>9-bolt.

Fact.

 

I don't care what a magazine writer says either.....It was the GM TESTS that intrigued me!

 

Apart from those being IRS units you forget one thing. The C4 Corvette and the Viper use the Dana44HD or super Dana 44 and it's NOT the same a a reg. Dana 44. It uses a Dana 60 sized pinion.

 

Where did you read it?

Oh.

 

I shoulda added the next sentence...

"Elimination of C-clips in the Borg-Warner and the use of tapered roller bearings at the wheels are additional strong points of the design."

 

to add some more tech, not to argue:

the D44 also has bolt in axles, and tapered axle bearings

 

And more tech about the Dana axles, it has larger axles that have bigger 30 spline size.

 

.....and yet it failed GMs tests, but the smaller axles didn't.

I dunno WHERE the failures were. Possibly at a point that didn't stres the axles themselves.

 

All of the Dana 44s that I've seen had 28 splines.

 

the d44's used in third gens have, without a doubt, 30 spline axles. i ordered a new set for my d44 from moser, 30 spline

 

I haven't been in one of those, but the Jeep and GM truck 44s had 28 spline axles.

 

Early Jeep dana 44s started with 19 spline and then switched to the 30 spline and the GM dana 44s units are 30 spline. The Dana 30 is 27 spline.

 

Guess that shows how well my memory is working.

 

I have seen a 9 bolt break and axle where a 12 bolt didnt. Doesnt mean 12>9".

From MY personal experiences, i built my 86 TA with a 355, unported vortec heads, 230 .050 duration cam, no stall with 3.07 gear in a good 9 bolt. 1 trip to the track had the damn gears whining.

I didnt even have a damn stall!! Pathetic.

My buddies 9 bolt a few weeks earlier had the pinion bearing lock up, slap full of fluid, does that make the 10 bolt better than the 9 bolt?

As stated, everyone ditches the 9 and 10 bolt for something better. Not to mention, BUILD a 9 bolt and a D 44 and then beat on them, the 9 bolt will bitch out WAY sooner than the 44.

 

Not to take sides with 9s being better than danas but your talking about the failure of a 20 something year old rearend. Thats not really a fair comparison to the article since the article was talking about them when they were new. Theres no telling how much abuse was thrown at your rear before u took it to the track.

Now that being said i have a 9 bolt myself that was supposedly "tight" when i bought it but did nothing but one wheel peels. So..into the rear i went to rebuild it. I like the design of them to be honest. Very simple and straightforward. Would i still take a dana if one came up cheap...? Hell yes. The big advantage of the dana to me is the bigger ring gear, more splines on the axle, and more of an aftermarket for the posi units. Those three things right there, in my mind, set the dana leaps and bounds ahead of the 9 bolt.

 

FYI, yes, the 9 bolt i mention was from behind a 305 and was well maintained with only a bit over 50 K miles.

So yea, VS the 370 HP or so with no stall, pathetic that it went out like that.

Now, as mentioned, Eric(ESC), a mod on this forum has been beating the snot out of his for 20+ years with no problems, rebuilds and it is still going, and he has engines in the 500 HP range and even Autocrosses VS me taking it to the track 1 time.

Case closed.

 

No worries, I had a 9 bolt kick the bucket backing out of a parking spot...... It was behind an LO3