Has anyone failed a Dana 44 ring & pinion??
02-17-2006, 09:46 AM
#1
Safety Car
Thread Starter
Has anyone failed a Dana 44 ring & pinion??
I stopped at my local GM dealership and learned that 3.45 ring & pinions are no longer available for my 1996 Dana 44 rear end.
Parts manager said this probably is because there was no demand for them.
I have seen previous posts asking how much power a Dana 44 can handle......my question is more specific to the factory Dana 44 with the factory 3.45 gear set.....has anyone failed one of these units and if so how???
What is the weak link in a Dana 44??
As they say curious minds need to know....
Parts manager said this probably is because there was no demand for them.
I have seen previous posts asking how much power a Dana 44 can handle......my question is more specific to the factory Dana 44 with the factory 3.45 gear set.....has anyone failed one of these units and if so how???
What is the weak link in a Dana 44??
As they say curious minds need to know....
02-17-2006, 12:27 PM
#2
Drifting
Member Since: Feb 2002
Location: Little Rock Arkansas
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You can break anything man... It largely depends on what you're doing with it. Hard, stick-shift launches on sticky tires will take its toll... I know this all too well. However if you're looking for ideas on what breaks I'll give you my opinions on failure from most fragile to least fragile...
The outer drive spindles are the most fragile piece, particularly if you don't pay attention to your wheel bearings. Worn wheel bearings create a ton of heat and soften the already poorly heat treated stock units. We re-heat treat them and cryo-treat them; I haven't had anyone break them down into the 9's. Past that you will be having a set of 300M spindles made. Next is the posi-traction unit; the spider gears and cross-pin are notorious for failing under hard launches. I polish the cases, rebuild them with new spiders, shims, clutch pack, and cross-pin and assemble them VERY tightly; then we cryogenically treat them as well. Usually good for mid to low 10's on auto cars and mid to high 10's on sticks; but they ARE a consumable if you're doing a lot of racing. This is due to the nature of setting them up so tightly but in order for them to live they have to be done that way. Once you're in the bottom 10's or faster the only real way to go is a full spool... However, the Quaife LSD used by a lot of road racers is available for the Dodge Viper so therefore that tells me it will go in our rears as well. Additionally a new locker-type carrier is about to be released. The problem with the posi-unit however is two-fold; when it breaks oftentimes it jams a chuck of spider gear between the ring gear and case and busts a hole in the diff case itself. Not to worry, it can be TIG welded back up and machined to like new; that's the beauty of aluminum. The posi failure is also what generally causes a ring and pinion failure too. The ring and pinion is not all that fragile and provided it is set up properly and maintained properly a good ring and pinion (and the factory Dana gears are as good as any aftermarket) will last years under pretty heavy abuse. I've got a set of 3.31 D44 gears that have seen an insane amount of abuse and they show hardly any where. The diff case itself is more fragile than the ring and pinion, but only when it is no longer just a "housing" but becomes a moving part of the suspension... If you don't understand what I said, it's this: ANY MOVEMENT WITHIN THE DRIVELING CAN CAUSE CASE FAILURE! If your differential mounting bushings aren't in top shape (and preferably polyurethane or solid Delrin if you're racing), if you torque arm (c-beam) isn't properly tightenend and all of the ancilliary suspension components sufficiently torqued (and checked periodically) you will be opening yourself up for failure. The torque arm is probably one of the most critical aspects; as the C4 corvette has no transmission crossmember but relies upon the "hard" mounted differential to provide transmission support via the torque arm. While it works nicely it does present some problems regarding the rear end. When you accelerate the tailhousing of the transmission attempts to move upwards. With a cross-member this movement is not allowed. With the torque arm arrangement, with particular emphasis on one that isn't tightened properly, the tailhousing moves upwards on launch. Providing your car makes a pretty fair amount of power and you've hooked reasonably well (which C4's ARE capable of doing) any movement within this area puts a shear load on the pinion nose of the differential case. The majority of MAJOR (ie., unrepairable) failure D44's I've seen has been this type. The whole front section where the torque arm bolts and the pinion gear attaches simply fractures. Think of it as two opposite forces acting upon one another, one has more give and allows its adversary additional movement that ultimately causes failure of the more highly leveraged piece (the diff). So the proper torque of the driveline is a MUST. It evidences itself in other ways in cars that don't have the power to bust the rear... These cars tend to get squirrely (particularly on hard upshifts) if their is slack, they will noticably kick out to one side. The shifter will also move up and down...
The stub axles are STRONG!!! They are 30 spline units with 1350 series u-joints. The only thing we do is cryo-treat them; I don't know of anyone who has broken one. They are pretty bulletproof stock, unlike the 26 spline drive spindles.. The halfshafts are remarkably strong in these cars as well... Automatic equipped C4's have gone easy 10's and some 9's on stock aluminum halfshafts. Generally the biggest problem we see here is u-joint failure. The good u-joints usually don't break but the crappy OEM-style u-joint straps cause sharp pressure points on the u-joint caps and cause them to shatter which usually tears up the halfshaft. Billet or another form of machined caps solve this issue. Stick cars such as mine have gone high-9's on stock, cryo-treated aluminum half-shafts while others (including auto equipped ones) have twisted them in the 10's and 11's. I think it's greatly a matter of how tightly the car is setup and what type of routine the driver follows with regards to their longevity. However a swap to steel or chromoly (preferable) will eliminate this worry. Now we're to the u-joints; there is only one u-joint to have in my opinion and that is Lakewood's 23021 1350 series u-joints. They are KILLER, but EXPENSIVE, particularly when you need five or six of them (if you convert over from the 1310 pinion yoke to the bigger 1350 you need six)... We cryo-treat them for additional strength. I've got the same u-joints in a big block Super Stock "C" Corvette that is backhalved runs a G-Force 4-spd and ET's in the 9-teens at 148 with a short time in the 1-teens; they've been in there over four years and show no signs of giving up. Typically I replace u-joints yearly but these suckers just don't seem to need it. I've never broken one...
I think that about covers the fragility issues succinctly. Please don't be misled by thinking this is a weak rear. Size wise it's comparable to the venerable GM 12-bolt. Jeeps have been putting stupid amount of torque through the 44's (with 5:1 transfer cases in rock crawlers) on HUGE, HEAVY tires and rarely break them... Unfortunately we just have more moving parts. But it can be made to withstand, IMO, passes as quick as mid-7's but it takes a lot of time and money... But when you look at the cost of doing a 4-link or ladder bar swap (the right way) the cost is still much less to do a heavily built 44... The entire key is eliminating movement and adding strength where necessary, just the same as it is for anything else.
-Jeb
The outer drive spindles are the most fragile piece, particularly if you don't pay attention to your wheel bearings. Worn wheel bearings create a ton of heat and soften the already poorly heat treated stock units. We re-heat treat them and cryo-treat them; I haven't had anyone break them down into the 9's. Past that you will be having a set of 300M spindles made. Next is the posi-traction unit; the spider gears and cross-pin are notorious for failing under hard launches. I polish the cases, rebuild them with new spiders, shims, clutch pack, and cross-pin and assemble them VERY tightly; then we cryogenically treat them as well. Usually good for mid to low 10's on auto cars and mid to high 10's on sticks; but they ARE a consumable if you're doing a lot of racing. This is due to the nature of setting them up so tightly but in order for them to live they have to be done that way. Once you're in the bottom 10's or faster the only real way to go is a full spool... However, the Quaife LSD used by a lot of road racers is available for the Dodge Viper so therefore that tells me it will go in our rears as well. Additionally a new locker-type carrier is about to be released. The problem with the posi-unit however is two-fold; when it breaks oftentimes it jams a chuck of spider gear between the ring gear and case and busts a hole in the diff case itself. Not to worry, it can be TIG welded back up and machined to like new; that's the beauty of aluminum. The posi failure is also what generally causes a ring and pinion failure too. The ring and pinion is not all that fragile and provided it is set up properly and maintained properly a good ring and pinion (and the factory Dana gears are as good as any aftermarket) will last years under pretty heavy abuse. I've got a set of 3.31 D44 gears that have seen an insane amount of abuse and they show hardly any where. The diff case itself is more fragile than the ring and pinion, but only when it is no longer just a "housing" but becomes a moving part of the suspension... If you don't understand what I said, it's this: ANY MOVEMENT WITHIN THE DRIVELING CAN CAUSE CASE FAILURE! If your differential mounting bushings aren't in top shape (and preferably polyurethane or solid Delrin if you're racing), if you torque arm (c-beam) isn't properly tightenend and all of the ancilliary suspension components sufficiently torqued (and checked periodically) you will be opening yourself up for failure. The torque arm is probably one of the most critical aspects; as the C4 corvette has no transmission crossmember but relies upon the "hard" mounted differential to provide transmission support via the torque arm. While it works nicely it does present some problems regarding the rear end. When you accelerate the tailhousing of the transmission attempts to move upwards. With a cross-member this movement is not allowed. With the torque arm arrangement, with particular emphasis on one that isn't tightened properly, the tailhousing moves upwards on launch. Providing your car makes a pretty fair amount of power and you've hooked reasonably well (which C4's ARE capable of doing) any movement within this area puts a shear load on the pinion nose of the differential case. The majority of MAJOR (ie., unrepairable) failure D44's I've seen has been this type. The whole front section where the torque arm bolts and the pinion gear attaches simply fractures. Think of it as two opposite forces acting upon one another, one has more give and allows its adversary additional movement that ultimately causes failure of the more highly leveraged piece (the diff). So the proper torque of the driveline is a MUST. It evidences itself in other ways in cars that don't have the power to bust the rear... These cars tend to get squirrely (particularly on hard upshifts) if their is slack, they will noticably kick out to one side. The shifter will also move up and down...
The stub axles are STRONG!!! They are 30 spline units with 1350 series u-joints. The only thing we do is cryo-treat them; I don't know of anyone who has broken one. They are pretty bulletproof stock, unlike the 26 spline drive spindles.. The halfshafts are remarkably strong in these cars as well... Automatic equipped C4's have gone easy 10's and some 9's on stock aluminum halfshafts. Generally the biggest problem we see here is u-joint failure. The good u-joints usually don't break but the crappy OEM-style u-joint straps cause sharp pressure points on the u-joint caps and cause them to shatter which usually tears up the halfshaft. Billet or another form of machined caps solve this issue. Stick cars such as mine have gone high-9's on stock, cryo-treated aluminum half-shafts while others (including auto equipped ones) have twisted them in the 10's and 11's. I think it's greatly a matter of how tightly the car is setup and what type of routine the driver follows with regards to their longevity. However a swap to steel or chromoly (preferable) will eliminate this worry. Now we're to the u-joints; there is only one u-joint to have in my opinion and that is Lakewood's 23021 1350 series u-joints. They are KILLER, but EXPENSIVE, particularly when you need five or six of them (if you convert over from the 1310 pinion yoke to the bigger 1350 you need six)... We cryo-treat them for additional strength. I've got the same u-joints in a big block Super Stock "C" Corvette that is backhalved runs a G-Force 4-spd and ET's in the 9-teens at 148 with a short time in the 1-teens; they've been in there over four years and show no signs of giving up. Typically I replace u-joints yearly but these suckers just don't seem to need it. I've never broken one...
I think that about covers the fragility issues succinctly. Please don't be misled by thinking this is a weak rear. Size wise it's comparable to the venerable GM 12-bolt. Jeeps have been putting stupid amount of torque through the 44's (with 5:1 transfer cases in rock crawlers) on HUGE, HEAVY tires and rarely break them... Unfortunately we just have more moving parts. But it can be made to withstand, IMO, passes as quick as mid-7's but it takes a lot of time and money... But when you look at the cost of doing a 4-link or ladder bar swap (the right way) the cost is still much less to do a heavily built 44... The entire key is eliminating movement and adding strength where necessary, just the same as it is for anything else.
-Jeb
02-17-2006, 01:19 PM
#5
Drifting
Member Since: Feb 2002
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Originally Posted by RED-85-Z51
no to hijack this thread, but how much stronger is a D44 to a D36 on an auto car?
-Jeb
02-17-2006, 01:24 PM
#6
I participate in quite a bit of "spirited Driving", Hard launches, powerbraking...etc etc...
It is a mostly stock 85...Ive done a few free mods to it.
Gutted Cat
Muff. elims
descreened MAFS
Throttle performance chip
Custom PROM chip
K&N Air filter with open Air box
TB Bypass
you know, poor mans modifications.
Do you think Icould hurt it?
It is a mostly stock 85...Ive done a few free mods to it.
Gutted Cat
Muff. elims
descreened MAFS
Throttle performance chip
Custom PROM chip
K&N Air filter with open Air box
TB Bypass
you know, poor mans modifications.
Do you think Icould hurt it?
02-17-2006, 03:04 PM
#7
Drifting
Member Since: Feb 2002
Location: Little Rock Arkansas
Posts: 1,952
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Absolutely you could hurt it... That's kinda the way the 35/36 series is. Like I said, I've seen them break on street tires in the 13's and then I've seen them go 10's on full slicks without ever breaking. Largely breakage is a factor of power and traction on these cars. I'm not saying you don't have enough power to break one but it is unlikely you will do so on street tires at the level you're currently at. I think most of the 36's will take 12's pretty easily provided they're maintained properly and you have a sound racing routine. My wife's D36 probably has well over a hundred 11 second passes on it and the only mods it has are a rebuilt (and tight) posi-carrier, a set of Richmond 3.75:1 gears, and cryo-treatment. It runs 26x11.5x16 ET Streets at these times; I don't think I would be comfortable pushing much more through it but it seems to be okay with 450 hp.
-Jeb
-Jeb
02-17-2006, 04:48 PM
#8
Le Mans Master
One other point that helps any diff. live longer is, when you roll up to the line with the clutch shoved in, once you stop, hold the brake and let the clutch out slightly to take up the slack in the driveline. That way, when you launch, it dosnt hammer the driveline slack as much. Hope this makes sense.
