Broke Diff again!!!!

[VIPERMIKE]

I was driving normal and then crunch!!! This is the third time, I should have never put the 3.55 in the car. I'm tired of these problems....

 

[ARMORGOD]

Very sorry to hear about the diff failure. It sounds kind of funny, though, as lots of others are running 3.55s and 3.73 mit kein problem. Hope you can get it fixed without any more issues.

 

[JoeBob]

I have two SRT's with 3.73's and neither has been an issue but keeping the ole fingers crossed

 

[Krazy PSI]

ViperMike, if possible rebuild the diff with a crogenically treated gear set. It also wouldn't hurt if you went a step further and added a Quaife to that package. Hope this helps.
---------------------------------
2003 SRT-HEFFNER TWINTURBO "1040RWHP&1135RWTQ"
1999 DIABLO VT-HEFFNER TWIN SUPERCHARGED "620hp&740tq"
2005 MERCEDES CL65-HEFFNER MODIFIED&TUNED "650HP&830TQ"
2005 MURCIELAGO ROADSTER-HEFFNER SOON TO BE TWINTURBOED
2005 AUDI S4 CABRIOLET HEFFNER RS6 ENGINE CONVERSION (WIFES CAR)
2003 HUMMER H2 HEFFNER WHIPPLECHARGED/6SPEED TRANSMISSION CONVERSION

 

[SnakeEye]

Cryogenically treated or not, make sure you get the hd gear set - hypoid cut. Now that Mopar has lowered its price on these it may be a given that most resellers are selling the hd’s (not sure); in the past some offered a set that was either straight or spiral cut - this differs from OEM spec.

 

[kmg99]

Mike -

Changing the gear ratio does not increase the loads on the differential. The viper is easily able to exceed skid torque with your new ratio or the stock ratio, so the tires dictate the maximum torque load the differnetial will see in use. The 3.55 ratio does decrease the pinion gear diameter, making it slightly weaker, but this is not what is failing in your vehicle.

A couple of things come to mind: the Dana 44 axle assembly used in the viper uses shims to preload the differential in to the case. These need to be readjusted quite frequently when changing ratios due to the different thickness of the ring gear to offset the smaller pinion diameter when going to a "deeper ratio". Maybe your tech has not made this adjustment? Second, I always find when having differential ultimate strength issues it helps to put in a little extra preload when setting the differential.

 

[VIPERMIKE]

I have the cryogenically treated gears, and the hd gear set - hypoid cut. I think the posi went too.

 

[Skip White]

Driving normal, no way this setup was installed properly in my opinion, or have you did some really hard launches?

Where did you have the work done, and what brand of components?

Skip

 

[VIPERMIKE]

The sad thing is, I haven't even had a chance to pound the car yet. I will post who did the install if they don't take care of me. I don't want to give them a bad name.

 

[Russ M]

I wonder if those wheels you have could be part of your problem. Those 20" HRE wheels are super heavy weights, which probably added 10-15lb's of rotating mass to each corner.

 

[Skip White]

The wheels could not have been any heavier than the oem. HRE's are usually a good five pounds lighter than the oem's. Yes they are a contributor, but the not in this case. Mike says he hasn't even got on it yet. The 20's also have a lower aspect ratio than the oem, so they end up about the same rolling diameter. The 3.55's would relieve load if anything, not increase it. I wonder if Mike upgraded the cross pin. If not this would only be a factor when doing a hard launch.

Skip W

 

[VIPER D]

I wonder if those wheels you have could be part of your problem. Those 20" HRE wheels are super heavy weights, which probably added 10-15lb's of rotating mass to each corner.

I don't think that theyu can be any more heavier than the stock wheels with run flats


vd..

 

[Russ M]

HRE's at least for Gen 2's are heavier than stock. HRE is not known for their performance gains, more of a bling bling wheel. I would almost be willing to bet they are considerably heavier than stock. Not to mention that they are 1 inch bigger which means much heavier.

 

[29OUTLAW]

I hate being a Monday morning quarterback but I learned years ago never to screw with a factory-assembled rear-end. Back in 1995 I decided my beautiful Firehawk needed 4.10 gears. Changing those gears turned that car into an undrivable heap. I went with 3 different set-ups from 3 different shops and it was all the same. Those gears sang so loud you could hear me coming from 2 blocks away. I would have given anything to return it to the original gears it came with but by then it was too late.

There’s no doubt the stock Viper gears of 3.07 are anemic, but there’s no way I would ever mess with it. Been there, done that.

 

[DynoDaddy]

4.10's and esp 4.30's and 4.56's in any car make noise 85% of the time. Even some 3.73's in newer cars have a little whine to them. Even when going to a new Richmond gearset whine will occur. It is jsut hte nature of the gears and the way they are manufactured.

 

[Skip White]

Mike has a 3.55 in the car, none of the above. The new two cut style gear as I believe it's called from Unitrax does not make any noise what so ever. As I said noise is usually from inproper setup. Some positrack rearends will have what they call a 3mph whine, but this is hardly noticable.

As for the HRE's weighing more than stock, since they are 20's the same at most. I will be curious to know what happend to the rear end. No warranty from the factory on this.

Hard launch when cold is risky on the diff. Winter is here, so remember warming up the engine does nothing for the diff. Takes at least 15 minuets to warm the diff up, and the trans. Quaffie will be in all these cars before long.

Skip

 

[29OUTLAW]

4.10's and esp 4.30's and 4.56's in any car make noise 85% of the time. Even some 3.73's in newer cars have a little whine to them. Even when going to a new Richmond gearset whine will occur. It is jsut hte nature of the gears and the way they are manufactured.

You aren’t kidding. To make matters even worse, those F-Body cars only had 8” ring gears!!

The bottom line is I’m done with all performance upgrades on any of my cars, trucks, or boats. I’ve messed up way too many. A while back I discovered that something as benign as an exhaust swap on a 502EFI boat engine caused it to lean-out so bad it would have surely detonated had I not found the problem. It seems every time I mess with factory engineering, I loose. I guess those guys are pretty smart and do things a certain way for a reason. Anyway, I’ve decided to stick with reliability.

 

[Brian E]

I have the Unitrax 3.55 setup in my 04. The setup has been flawless. It really comes down to installing good parts, by qualified mechanics.
Another point to remember is that the 03 cars didnt have hardened carrier pins or bolts. The Unitrax parts are heat treated.
Doesnt anyone remember all the broken rears from a year or so ago?

 

[Viper X]

Guys,

I'm on my fourth 3.55 ring and pinion set in 9,000 miles. Hardened pin, cyro treated gears, wired in bolts, amsoil, etc. Lost the hydrolock last time. Next time, 3.07's or Quaiffie (spelling?).

I'm in so Cal too, and it really never gets that cold here.

No hard launches. Hard launches are really impossible with run flats anyway. Run flats = no traction, but that's another issue.

Good luck Mike

 

[Skip White]

Mike was it going into second when you lost the diff? It seems to be a hit and miss thing with these diffs going out. Some people drive the hell out of there car, and never have a problem. Needless to say the diff is a weak point, but I'm really mistified by the fact some break, and others don't.

Some people are just driving along, and it goes, I've heard. I really don't get it.

Skip

 

[Russ M]

SRT diffs seem to be nearly identical to Gen 2 diffs. And Gen 2 diffs are fairly bullet proff from the factory. If they are breaking its not the driving its the assembly/installation.

 

[VIPERMIKE]

I have the 3.55 ring and pinion set, hardened pin, cyro treated gears, wired in bolts, and amsoil.

Someone tell me more about the Quaffie, and it's price.

 

[Kai SRT10]

Someone tell me more about the Quaffie, and it's price.

Quaife is $2890 plus labor to remove it, replace it, and ship it to and from Texas (Taylor Race Engineering.)

I'm getting mine replaced with a Quaife first of the year. Will post here when I get a chance to drive it.