how strong is this rear end? how much hp can it hold up to? what kind of 1/4 mile ETs can it hold up to? can it be rebuilt even stronger than stock? what does it run to rebuild a tranny? are you going to have to run a ford rear end if you are running very much power? i know the dana 44 is better than the auto dana 36s but not sure what exactly that means and by how much

 

There is no definite torque limit on the D44 or the transmission. Though both have their 'ratings.'

The D44 is working fine for people here running 10's, should be ok until the high 9 second range.

 

thats pretty impressive if they can make it in the 9s. is there anyway to rebuild them stronger?

 

I dont see any way how, at that point people switch to the Ford 9" or Dana 60.

 

dana 60? i didnt know such a rear end existed? is that what comes in the dodge vipers? can you be patient and explain this as well?

 

Dana 60's came in trucks and some old 60's-70's chryslers had them. The Dana 44 in our cars can be cryoed, and will live in the 10's and even the 9's. I had my driveshaft, differential assembly, halfshafts, and spindles cryoed and nothing has broke.

 

The Viper has a Dana 44. The Dana 60 is not an IRS setup and takes a ton of fab work just like the ford 9" to do. There is a lot of stuff that can be done to the Dana 44 IF need be, but people like JBurnett have proven it isn't really necessary.

 

i think you are right it probably isnt nessecary but out of curiousity, where did you get all your drivetrain crynoed at? how much was it?

 

Run a Dand 44 long enough and hard enough and it will fail.
Most of the guys running low 10's or even 9's with a Dana 44 are launching soft and using juice or turbos.

 

deepfrezzecryo.com i thank thats jebs place in little rock

 

I believe the gear selection has more to do with the amount of power a Dana 44 will hold. A set of 4.10's will NOT be as strong as 3.07's.

Vic

 

Dana 60's weigh a ton(well 1/2 ton) they are heavy.

 

It was Jeb @ Deep Freeze Cryo that did the work for me. It's been a year and a half ago since he did it, and I don't remember exactly what it cost. It seems like it was around $500. Contact Jeb, he can give you the details.

 

The Dana 44 with its 8.5" ring gear is essentially equal in strength to the much touted GM 12 bolt. It's actually a very strong rear end. The biggest weak spot in them is the drive spindles and the posi-unit. The drive spindles are horridly heat treated; the examples I've actually scaled were in the 26-28C Rockwell scale which is VERY soft and is one of the reasons they tend to twist in half. Poor rear wheel bearings can cause spindle failure as well; if the bearings are going out and are producing heat they can further anneal the spindles and cause them to fail. The posi unit is the main cause of failure within the diff itself. Typically either the pin shears or teeth are broken off of the spider gears causing failure of other components. It's actually fairly rare for the halfshaft to fail, they are afterall rather short and very stout (at 3.5" dia), I've never broken one and the ones I have heard of breaking I suspect there were other conditions that contributed to it. The R&P as stated is equivalent to the 12 bolt GM and it is VERY rare to have any problems with them and when they do occur it is usually the result of posi failure.

There are a few things that can be done to the D44 to increase their durability; the first mentioned is the cryogenic processing that my company performs. I can guarantee with no qualms a 100% increase in durability and strength; generally the figure is much higher but I will actually GUARANTEE that percentage. I recommend the entire differential being processed as well as the halfshafts and drive spindles. Careful blueprinting of the clearances and careful assembly also go a long way in helping the longevity of the D44 (and its smaller brother the D36). I know Speed Demon motorsports builds some billet drive spindles (I've cryoed a pair of them as well) that are essentially bulletproof but do come at a substantial price, but are probably worth it to those running serious ET's with their IRS. Denny's offers "Nitrous Ready" carbon-fiber halfshafts and we will be offering our 4340 chromoly "Cryo-Shafts" as well in the near future.

For a perspective on how much power a D44 assembly will take my particular unit which is the stock system in my 1990 Vette that has been upgraded only with cryogenic treatment, a 4.09 gearset, and careful assembly has gone as quick as 9.91 at 141 on a nitrous fed 396" engine. And I DON'T baby it out of the hole! It's a ZF stick car with a Street Twin clutch, I sidestep it at 5500-6000 rpm and get on the button right after the clutch engages. I have yet to break anything since we started "beefing" them.
-Jeb

 

What will the weight of these be compared to the stock units?

:eek: :steering: :smash: What kind of 60' times are we talkin about?

 

Low 1.5's with one or two 1.48's...

The weight of the chromoly ones will be roughly the same as the aluminum shafts (.100" wall tubing).

I forgot to mention this above: I WILL be going 8's this year on the IRS...With the addition of the new mill and the t-brake TH400.
-Jeb