Dear Jon, just to say THANK YOU for your superb service. Packages arrived this morning safe and in perfect order. CB in the UK
• C.B. UK
Jonb, Thanks so much for helping us out! We were in a jam, with no rear-end just days before a 3 day event. In twenty years of buying Viper parts and dealing with Viper people, I can honestly say you have always been one of best best people in the business and the Viper community. Thanks for being there for all of guys that turn our own wrench. My son's and I are very grateful your business is surviving in such tough times. Now that were slowly getting back into racing, we will be turning to you for our Viper parts supply line. Sincerely, Todd
• Texas Todd

Got Gears?

Okay, so you're a big-shot and now comfortable with the massive torque and acceleration of your Viper. You've put a good amount of miles on the clock, and are looking to upgrade the performance.  You've done the smooth hoses, K+N filters, and maybe added a high performance exhaust. You'd LIKE to add 50-70HP, and experience that RUSH that HP brings. Maybe you've been annoyed by an occasional Z-06 or Rice-Rocket...or perhaps your buddy has a blower? You quickly determine that while the first +10 or +20 HP are relatively inexpensive.... the NEXT 50+ are likely to cost thousands! What is a Viper owner, bored with a mere 400 to 600 HP to do? GEAR DOWN !

Without a doubt, a rear gear swap is my "# 1 Bang-For-Buck Upgrade." For well under $1200, including labor, you can make your 450 HP Viper feel like you gained 70 HP of pulling power. Gen-1 owners now immune to 400 HP can feel like 60 HP was added. Gen 3 feels like 75 HP and G4 a whopping 90HP!  Now That's acceleration. You are not actually creating any HP....you are just allowing the existing HP to get down to the rear tires about 15% faster.

The 3.07 choice has nothing to do with Corporate Average Fuel Economy, because so few Vipers are built each year that even if they achieved only 1 mpg, they would not affect CAFE by even a tenth of a point. In order to keep our Federal Gas Guzzler tax down, all Vipers are given a relatively meek 3.07 rear end ratio. This, coupled with the annoying but mandatory Skip-Shift solenoid, allows the Feds to see an amazing 21+ highway fuel mileage in our Vipers.  So, the 3.07 ratio renders our 5th and 6th gears relatively lame, while 1st thru 4th gears are still pulling monsters. But they can perform even better.

Just by swapping to a 3.55 final drive rear end ratio, (under $1200 installed) you can send 15% more torque to the rear wheels at any given RPM. The "Seat Of The Pants (SOTP) feel is amazing, and 1st thru 4th gears now have 15%+ more GRUNT......and even 5th gear places you square in the cruiser's power band. 6th gear, a rarely used "option" for most of us, now becomes a daily-use gear, especially on long cruises. In fact, when you cruise in 6th with a 3:55 rear gear, you can get BETTER gas mileage than while cruising in 5th gear with the OE 3.07. Another bonus: The car SLOWS faster when you lift off the gas. Better braking!

Is this too good to be true? The SOTP of +70 HP, and better braking, for under $1200 installed? What Am I missing ?! The downsides are few: Your 195 mph Viper is now reduced to a 165 mph top speed.....but you will get there 15% faster! In stock trim you can stretch 1st gear to 62 mph at redline.......with a 3:55, you shift at 52. If you spend a lot of time on the road course, you are shifting a bit more.....but really pulling out of most corners at a faster rate. If you are a quarter-miler, you might have to shift just as you reach the 1400' mark. Gas mileage goes down 15%.

But acceleration is just flat-out improved 15%. The "Stop-Light Grin Factor" is real, and instant. "I should have done this a long time ago" say most recipients of this 3:55 organ transplant. "It's like getting a new girlfriend" I said way back in 1993, (when I was single.)  The analogy stuck, because Coleen J. called recently to say she would let me know if her 3.55 is anything like getting a new boyfriend!

Other downsides: Your tranny and rear end will run marginally warmer with a 3.55.

Very little factor here, eliminated by simply increasing the frequency of fluid swaps to 25% sooner than normal. Vipers already pushed to 700HP or beyond might choose a 3:33 instead.....a mere 8% rear torque boost, but easier to control the massive wheelspin that will otherwise develop. At 550 HP, the gear "feels" like 82 more HP.  What about 3.73? Or 4.11? Don't Go There!

O.K, a stock 400HP Gen 1 can handle a 3.73, but these ratios really amount to a severe service cycle on rear end internals and the tranny output shaft. These steeper gears are more likely to whine. And be VERY careful with the loud pedal. It's difficult to roll-on the throttle smoothly, especially in corners, with gears this steep. Scary. If you insist on 3:73, be certain to swap trans and rear end fluids in half the time as the service manual suggests.

With the possible exception of the new 08-09 Visco-Locks, swapping the 92-06 rear gearset is not rocket science. Many Viper-savvy or Jeep-savvy dealers can swap the gears. Any good 4X4 shop or Corvette tuner has done bunches of Dana-44 gear swaps.

Mopar even makes a COMPLETE rear end, but the MSRP is $2258. Whereas even BETTER gears, speedo converter Gen 1-2, and complete new internals are about $650 or less, just for the upgraded parts. Gen 3-4 don't even need a speedo box...the ABS and PCM combine to measure the true speed.  Gen 4 rear ends are stronger and very tricky.  Don't trust a Gen 4 swap to just anyone. Gen 4 experience matters.

Not all gears are created equal. Insist on hardened, and even cryogenically treated and polished gears. Stronger. Less friction, less heat, less likely to whine. Allow 6 hours labor for an experienced tech.  Available from PartsRack here!

Got gears? Get gears! You will NOT bedisappointed. Be Safe Out There.....