Gen 3 Diff Upgrade?

[Turk]

I'm looking to upgrade the diff on my 2005 and was wondering what people recommend? I was thinking of going Wavetrac with a 3.55 gear, but was wondering if there are any other suggestions out there. Since I don't take my car to the drag strip, and only track it once a year do I really need the 3.55 gear? Most of my driving is on the highways cruising through the mountains. Also if I upgrade the diff do I need to do the half shafts as well?

[Joel]

Lots of folks will have different ideas on this. Got my Unitrax upgrade to late rear end model specs with 3.55 gear and I really like it. Made 5th and 6th usable - 80+ mph in 6th is 1300-1400 rpm. Some folks modify the transmission or get a Trans-zilla upgrade to change 5th and 6th gear ratios. I track my car and find the gears more suited to fun and track driving - 3 and 4 are close, 5th will give about 145-150+ on back straight at Road Atlanta - if I'm that brave. My half shafts are stock but I am not a drag racer. I think the stock shafts will be fine. PM me if you have more questions.

[Nine Ball]

Wavetrac posi made a big difference on my high-hp car. The rear of the car used to kick out a little from a 60 mph punch, before straightening out. Now it takes off perfectly straight on the hit. 3.55 gears will wake up the Gen 3 nicely, especially in 1st gear. It will also make 6th gear far more useful on the highway.

Won't need upgraded half-shafts unless you are making a lot of power and launch hard at the drag strip, like I do. Stock half-shafts are pretty strong, as long as you never wheel-hop them. If you ever feel wheel-hop, lift off the throttle immediately. I never broke any, even with 1000+ rwhp. And that was with a lot of hard runs.

Tony

[Sonoman]

I traded in my 2005 diff to Unitrax for a 2010 Viper ViscoLok diff and had them install the new gears as well. I like the lock-up characteristics of the ViscoLok better than the old Hydra-Lok and the car is more predictable coming out of corners on the gas. As mentioned, the half shafts are OK for most conditions but they can break with severe wheel hop/lots of runs down the strip. Given the price of improved shafts I am waiting for one to go out before spending big bucks on new ones.

The original Gen 3 Hydra-Lok differential has an interesting design which requires one wheel to spin 3-5 revolutions before locking the diff and transferring more torque to the non-spinning wheel. On my Viper this tended to make the car feel a little squirelly, like it was doing a little two-step dance back there if you got on the throttle too suddenly. To me, the newer ViscoLok rear-end just feels more normal, like what I would expect from a limited-slip rear. Obviously, there are several options in LSDs for the Viper and it would be cool to try them all on a track and pick the one you like the best.

[Turk]

Thanks guys, I'll give Unitrax a call. I don't ever plan on increasing my horsepower so I'll just stick with the OEM half shafts.

[J TNT]

I bought from unitrax , dealt with Devon . They are top notch ! ;)

[Dan Cragin]

Here is some information I have from our website.

Why upgrade my limited slip differential?

Ever hit the gas on your Viper and have it go sideways instead of straight. This can be a scary experience!

From 1992 to 2010 the Dodge Viper came with a factory installed limited slip differential (LSD). 1992 -2002 used a Trac Lock, 2003-2005 used a Hydro-lock and 2008-2010 used a Visco-lock LSD. As the Viper’s power increased the LSD was upgraded to improve durability and traction.

The factory LSD units do a good job, but are limited in the power they can take and how they apply torque to the wheels.

There are three Performance Viper LSD units on the market now that can take nearly unlimited power levels and move between both free and locked positions much better than the factory LSD’s. The end result is superior traction and durability.

OS GIKEN “SUPERLOCK” 2003-2010 Vipers

The Super Lock is a true 100% locking LSD that instantly reacts and transitions smoothly from both free and locked positions, combining open differential driveability and limited slip differential performance and stability.
The OS Giken Super Lock features innovative technologies like an adjustable lock timing adjuster. Lock timing can be adjusted by replacing the springs in the pressure ring. Initial torque settings are also adjustable through cone springs located at ends of clutch stacks. This allows the Super Lock to be tuned to meet your exact needs for optimum performance.

WAVETRACK LSD 2003-2010 Vipers

The Wavetrac is made in the USA and uses high quality ARP hardware. It uses torque biasing worm gears instead of clutches to control the rear axles in the event of uneven traction. In clutch and plate LSD rear ends, the unit is trying to lock up and simulate a spool when a wheel loses traction and ensure that at least 50% of available torque is sent to the wheel with traction. A worm gear limited slip differential uses it’s gearing to send more than 50% of the torque to the wheel with traction. In other words, when one wheel begins to slip a worm gear LSD uses the mechanical leverage of its worm gears to transfer the torque the slipping wheel is receiving and send it to the other side. The Wavetrac differs from other torque biasing LSDs due to its unique and patented wave cam. The wave cam allows this Helical LSD to achieve full traction even when a wheel is unloaded.

TRU-TRAC 1992-2002 Vipers

The Detroit Truetrac is the first helical gear differential ever introduced into the automotive aftermarket. It remains a leading helical gear-type limited slip differential in the industry. Detroit Truetrac's proven gear design eliminates the need for wearable parts, resulting in maintenance free traction recognized not only for its toughness, but its smooth and quiet operation. Proven design, low cost and effective performance make the Truetrac limited slip differential the ideal choice for high torque applications where a smooth transition from locked to unlocked is needed. No maintenance - Just Traction.

[TowDawg]

I went with a Quaife unit and 3.33's in mine. I was thinking about FI and 3.55's would be too much if I went that route. It made 5th and 6th more usable on the street, but the back straight at RA still sucked and I was better off holding it at redline in 4th for the last part of the straight, than going to 5th. It would pull in 5th, but still not very hard.
After the trans completely ate the main shaft on another run down the back straight, I went with the Tranzilla built unit and changed out the 5th and 6th gear ratios in the trans while I was at it (like Joel mentioned above). Did I lose a little mpg on the highway by having a taller 5th/6th and 3.33's? Yeah, but do I give a damn? Hell no! It completely transformed the car both on the street and on the highway. I knocked 1.5 seconds off my lap times the next time at RA because I go straight into 5th and just keeps going without missing a beat!
Also, like Dan said, when putting the power down (especially out of a corner) the car hooks better and much more predictable.
As far as halfshafts, I'm still on my stock ones with no issue. Wheelhop and hard launches is what will destroy them.

[Turk]

I was thinking of going with a 3.33 gear, but since I don't ever plan on doing a forced induction system I figured the 3.55 would be perfect. I've already been snake-bitten once due to loss of traction in the rear, so I can't wait till I get a chance to pull the diff out this spring and upgrade that "wonderful" OEM diff.

[Mbccenter]

I do have a extra Quafie with 3:55 comple rear.

[Mamba003]

I went with the Giken with 3.33s and could not be happier. Stock the rear would drift instantly left at anywhere past mid throttle. Now at 613 to the wheels, still dead strait no matter throttle, or traction.

[Turk]

Oh boy. Too many options to pick from. I was originally thinking Wavetrac since I've heard nothing but good things about them. Devin from Unitrax suggested the Wavetrac. But now I should probably consider the Quaife and OS Giken. I think I've convinced myself of getting the 3.55 gear, but now I need to figure out which manufacturer. One thing I like about the Wavetrac that Dan posted above is that you still have full traction when one wheel is unloaded. Mind you I'm never pushing my car hard enough to create a situation like that.

[Revolution]

Always take you for a ride in mine man and you can feel and judge for yourself!

[TrackAire]

I'm looking to upgrade the diff on my 2005 and was wondering what people recommend? I was thinking of going Wavetrac with a 3.55 gear, but was wondering if there are any other suggestions out there. Since I don't take my car to the drag strip, and only track it once a year do I really need the 3.55 gear? Most of my driving is on the highways cruising through the mountains. Also if I upgrade the diff do I need to do the half shafts as well?

I went with the OS Giken spec'd by BBG with (cryo'd and mircro polished gears, safety wired fasteners, etc). There was a thread about the Wavetrac on the other forum. Look at the video on post 1 and my response on post 21.

http://forums.viperclub.org/threads/668211-Wavetracs-Differential-maybe-not-different-from-others-at-all.?highlight=wavetrac

I love the Giken with 3:55's and I also have the modified lower 5th and 6th speed transmission ratios. True close ratio's for any track or street condition. If keeping your motor hp stock, changing the trans ratio's and rear end ratio really make the car even more fun to drive. You don't "need" to change your gears, but I hate the feeling of running around a whole track in 3 gear....same with the street. The car feels much more lively when the engine is in its sweet spot.

For your needs, a Gen 4 LSD would be a great upgrade to your Gen 3 unit (crap in my opinion). The Gen 4 LSD is so good that a few years ago a member on the other site competed in the SCCA National autocross championship and came in second place with a Gen 3 convertible. That is saying something and the diff was the major upgrade to get the car on the podium.

I picked the Giken over the Wavetrac because at the time Giken was used by a lot of race teams, Wavetrac was just coming onto the market.

Cheers,
George

[Copperhead06]

I do have a extra Quafie with 3:55 comple rear.

Do you want to sell the rear ??

[Revolution]

Let me know Matt I have a gen 4 diff if your interested :)

[steve911]

Not to hijack the thread, but I would like to know more about the gen 4 you have available...

[Turk]

Is it worth just doing a Gen 4 upgrade? From what I've heard a gen 4 upgrade is around the same cost of putting in a Wavetrac (assuming I'm buying a new Gen 4 diff).

[Revolution]

Came out of my gen 4 with 7500km and was removed by Devin at unitrax!

[Turk]

If I upgrade to a Gen 4 diff (housing included), does my drive shaft length change?

[Sonoman]

If I upgrade to a Gen 4 diff (housing included), does my drive shaft length change?

No, the housing is the same on Gens 3 and 4. Right down to the spiffy "Fangs" logo looking back at you... :D

[steve911]

Unfortunately there are no more Gen 3 or Gen 4 diffs to be had. The only complete diff assy currently available is the Gen 5 diff. THat doesnt have 3.07's in it though . You get 3.55's.

If you have a broken Gen3 or 4 diif, the only thing available are parts that have to be assembled into the case.

I going to have a Gen 3 diff warrantied soon and it was a pain for the dealer to get all of the parts. As a matter of fact the hydroloc is not even available any more. A Gen 4 posi unit had to be substituted.

[Revolution]

Is it worth just doing a Gen 4 upgrade? From what I've heard a gen 4 upgrade is around the same cost of putting in a Wavetrac (assuming I'm buying a new Gen 4 diff).

I wouldn't buy a new Gen4 diff but a used one would be a lot cheaper!

[steve911]

Came out of my gen 4 with 7500km and was removed by Devin at unitrax!

How much are you asking for the diff?

[Viktimize]

Is it worth just doing a Gen 4 upgrade? From what I've heard a gen 4 upgrade is around the same cost of putting in a Wavetrac (assuming I'm buying a new Gen 4 diff).

The Gen4 upgrade will just give you LSD, it won't give you the driveability improvements of a 3.55 ratio. And if you're staying stock I would definitely want that better rear end ratio just to make 6th gear useable on all those road trips we are going to do this summer. (wink wink, nudge nudge)

Sorry to crap on your sale Ron. lol. Looks like you got some other interest though anyway. BTW, did you just mail your whole pumpkin out to Untitrax for the diff swap? I am looking at a diff swap too this year once I am done with the MCS upgrade.

[Revolution]

He still need the diff and gears Victor nothing changes the Gen 4 is a good upgrade if you get it for the right price!

[Viktimize]

He still need the diff and gears Victor nothing changes the Gen 4 is a good upgrade if you get it for the right price!

Ya you're right. Brain fart for me, ignore me. lol

So what's a "good price" a fellow local Viper brother might be able to get a gen4 LSD for?? :-)

[Revolution]

Already gone to Matt sorry!

[Redx]

Ya you're right. Brain fart for me, ignore me. lol

So what's a "good price" a fellow local Viper brother might be able to get a gen4 LSD for?? :-)
Pm'd, local to you with a gen 4 diff.

[Turk]

all those road trips we are going to do this summer. (wink wink, nudge nudge)

I'm already working on opening up my schedule for the summer so that I can make it out on more road trips.

[Turk]

Quick question. Do the stub shafts on my gen 3 work with a gen 4 LSD (in a gen 3 housing)? I've heard they are compatible, but when I looked up the part #'s the gen 3 stub shaft had a different part # then the gen 4 ones.

[Garron]

Quick question. Do the stub shafts on my gen 3 work with a gen 4 LSD (in a gen 3 housing)? I've heard they are compatible, but when I looked up the part #'s the gen 3 stub shaft had a different part # then the gen 4 ones.

You will need gen 4 stub shafts.

[Joel]

I used my '03 axles in the upgraded rearend no problem. Got my Unitrax upgrade from JonB. Went right in, used old axles, and went about my business after carefully breaking in my new gears.


Quick question. Do the stub shafts on my gen 3 work with a gen 4 LSD (in a gen 3 housing)? I've heard they are compatible, but when I looked up the part #'s the gen 3 stub shaft had a different part # then the gen 4 ones.

[Revolution]

Like I said Matt give Devon a call he will set you straight!

[Turk]

Like I said Matt give Devon a call he will set you straight!

Ya I'll call Devin. I should have thought about this earlier, my 3.55 gears from Devin landed 2 days ago.

[J TNT]

Your in good hands ! And will cut out the middle man ! ;)

[10BANGER]

I went with the Gen 4 upgrade and the 3.55 ratio all done by Unitrax. Devon really knows his way around rears. :t1567:

[PaulP]

So from reading this sounds like a 50/50 lol , will a gen 4 diff work in a gen 3 with stock gen 3 shafts?

[ACtechOPS]

I put a Gen 4 diff from a 2009 (3000miles) in my 2004 this winter. It bolts right in, use your original drive shaft and rear half-shafts. Only thing you need to buy new is a strap kit to reattach the drive shaft. My diff was a high miler and getting the half shafts off the stub axles was a huge PITA. Penetrating oil, 10,000lb straps to provide a constant pulling force and a 3' 2x4 driven by an 8lb sledge. The things you do when you don't own the puller.

[PaulP]

Awesome Thanks for the reply and tips ACtechOPS!
i ordered a gen 4 diff can't wait to install it.

[Garron]

So from reading this sounds like a 50/50 lol , will a gen 4 diff work in a gen 3 with stock gen 3 shafts?

The 'axle shafts' are the same.

There is a little 'stub shaft' on each side of the diff. They are different gen 3 to 4.

If you get a complete diff it may already have the gen 4 stubs

[ACtechOPS]

As long as you buy a complete OEM gen 4 diff, it will plug right in. The stub axle diameter and spline count are the same (2003-2010 use same OEM half shafts). I have another option that a buddy did. He bought a gen 5 diff, swapped the stub axles and put it in his gen 3. Even though the rear housing looks different, he said it bolted in no issues. His gen 5 stubs are currently for sale on the Alley. I picked up my low mile gen 4 diff for $1000 (Canadian, so that's about $800 US), probably the most economical way to go. It is mated to a TR6060, so my '04 now has a Gen 4 drive train.

[Stealth78]

Wow, this thread is awesome. Apparently I'm not the only one that hates my Gen3 diff... Definitely going to be one of my first mods, now to try and figure out which to go with. My car will probably be about 70% street/ 30% track, any suggestions that best suit?

[Sharky]

I have a Gen 4 diff in my 06 Coupe due to the fact that there were some grouches out of the teeth of a couple of gears on the factory. Works very well and since I run considerably more hp than factory through my car it was I believe a very good idea.

[Redx]

Is the Gen 3 diff housing the same as the gen 4?

[ACtechOPS]

From what I understand, the housings are the same but guts are different. Sitting side by side on the floor, you would be hard pressed to tell one from the other and I have had both together.

[Sharky]

From what I understand, the housings are the same but guts are different. Sitting side by side on the floor, you would be hard pressed to tell one from the other and I have had both together.

Exactly

[Garron]

Is the Gen 3 diff housing the same as the gen 4?

Same part number

[Joel]

What do you "hate" about it? There have been plenty of threads on this. If you don't like the action of the OEM Trak Lok ( I think that's what it's called) of the stock rear end then you might want to consider after market like Giken or Wavetrack. Why don't you call JonB, or Unitrax or Bill Pemberton. All were helpful to me when I first got my car and wanted to make some improvements to the gearing. I really like the 3.55 gear with Gen 4 upgrades that I got from Unitrax through JonB but you may want more. (I do track my car but not a lot. The biggest problem with my old rear end was it was said to be weak but there are lots of cars running around with "weak" rear ends. I did not have any other problems other than I did not like the 3.07 gear) But more costs more and you can easily spend upwards of $3000 for something you don't really need. I can' remember the site, but I think Unitrax used to have an explanation of different steps of the evolution of rear differentials for Vipers.


Wow, this thread is awesome. Apparently I'm not the only one that hates my Gen3 diff... Definitely going to be one of my first mods, now to try and figure out which to go with. My car will probably be about 70% street/ 30% track, any suggestions that best suit?

[Stealth78]

What do you "hate" about it? There have been plenty of threads on this. If you don't like the action of the OEM Trak Lok ( I think that's what it's called) of the stock rear end then you might want to consider after market like Giken or Wavetrack. Why don't you call JonB, or Unitrax or Bill Pemberton. All were helpful to me when I first got my car and wanted to make some improvements to the gearing. I really like the 3.55 gear with Gen 4 upgrades that I got from Unitrax through JonB but you may want more. (I do track my car but not a lot. The biggest problem with my old rear end was it was said to be weak but there are lots of cars running around with "weak" rear ends. I did not have any other problems other than I did not like the 3.07 gear) But more costs more and you can easily spend upwards of $3000 for something you don't really need. I can' remember the site, but I think Unitrax used to have an explanation of different steps of the evolution of rear differentials for Vipers.

The actual strength of the limited slip is what I can't stand. I haven't even had the car on track yet but even on the street on aggressive corners I feel like the car likes to boil the inside tire. I feel as if I'm having to really finesse the throttle and work the wheel more than I should need to. I feel as the diff is a bit unpredictable and with that it almost feels like the car wants to step out without warning.

[v10addiction]

Go to Unitrax or Taylor race, for sure.

They built the rear end in our world record Ballista among many others and we have never had a problem.

We also use them in our ACR-X's after the factory rears died.
Nothing compares to a full quaife.

Drag racing, road racing, street driving, the quaife is the answer.

As for the 3.55 gears, it comes down to where your using the car and your money.
More gear in the rear is for lower torque levels and more shifting.

Gear multiplication makes more power get to the wheels, but shifts come sooner and more often.
3.55 gears means less traction in all the low gears.

They higher the torque, the less gear needed and the bigger gap between shifts, but more importantly traction.

If you make big power, don't waste your time on gears, it will slow you down shifting and you will run the motor harder on the highway.

If your upgrading the rear end, most builders wont reuse your stock gears, so your most likely buying gears anyway.

Spend the extra money on a quaife, you wont regret it.

To put in simple terms, on a road coarse, you can shift in the corner with the quaife and most cases not lose traction.
Try that on your stock end, but let someone know beforehand, so they can film it for youtube.

A quaife gets in and out of corners faster.

Gen 4/5 cars have a simple version of a quaife, which is one of the main reasons they run so fast on the road coarse.

If your racing is limited to less than 140mph, you will see nothing from 5th and 6th gear anyway, even with 3.55 gears.
If you cruise more than anything, you will just be adding miles to your motor, and have to get the speedometer re-calibrated.

[Cowger]

If your racing is limited to less than 140mph, you will see nothing from 5th and 6th gear anyway, even with 3.55 gears.
If you cruise more than anything, you will just be adding miles to your motor, and have to get the speedometer re-calibrated.

I could definitely be wrong, but I thought I read somewhere that the PCM/ECU pulled speed from the tone rings on the wheels, thus no speedo recalibration was needed...

[Cowger]

The actual strength of the limited slip is what I can't stand. I haven't even had the car on track yet but even on the street on aggressive corners I feel like the car likes to boil the inside tire. I feel as if I'm having to really finesse the throttle and work the wheel more than I should need to. I feel as the diff is a bit unpredictable and with that it almost feels like the car wants to step out without warning.

This is exactly what I felt with the stock diff, and what I now don't feel with the Wavetrac I put in. You can literally feel the Wavetrac working back there, transferring power back and forth between the two rear tires as they approach their traction limits. Gives me enough time to back off a bit before being snakebitten (which I was with the stock diff).

I have no doubt that other aftermarket diffs will give you similar results. Can't imagine anyone has ever regretted upgrading from a stock Gen3.

Bryan

[Joel]

I didn't notice this with my stock gear or certainly not with the upgraded Gen4 differential - your rear end may need an oil and sure-grip additive/supplement change. I have had several friends have what sounds like the problem you are having go away with a fluid change - or at least get better. But if you apply too much throttle on cold tires you will break loose - not a rear end problem but a cold tire problem. I considered a quaife when I got mine but after talking to a few folks, I decided to try the Gen4 upgrade instead. I have been pleased and the 3.55 gears have made it easier to drive not harder. Yes you do shift a bit more but once you get used to it, it really doesn't seem to be much different on the street than the 3.07 gears - but it pulls much harder and is easier, IMHO, to drive than the stock gearing was. Try to find someone near you who has a different setup and then make your decision. I have had what I thought were fast, powerful cars over the years but nothing compares to the sheer torque and power of a Viper. As I said before, the HPDE will open your eyes and make you a better driver. Give it some time.


The actual strength of the limited slip is what I can't stand. I haven't even had the car on track yet but even on the street on aggressive corners I feel like the car likes to boil the inside tire. I feel as if I'm having to really finesse the throttle and work the wheel more than I should need to. I feel as the diff is a bit unpredictable and with that it almost feels like the car wants to step out without warning.