Rear Gears

[viperjim]

Mike, I am getting ready to get mine installed - did you get your speedo recalibrated too? I mean, if it's off by 5-8mph or so I can live with it. I rarely look at the speedo anyway.

If you have a Gen3 you do not have to recalibrate the speedometer. It is done thru the tire low pressure sensors.
I was going to pull the trigger on 3.55 last week but my installer has talked me into installing a Quaife differential at the same time. I guess he knows my abusive nature and was told by Unitrax about the common failure of the stock unit.

 

[boplaw]

Good to know. Thanks.

 

[Steve 00RT/10]

Swapping gears is, by far, the NUMBER ONE BANG 4 BUCK performance upgrade you can choose. SAVE YOUR MONEY on a supercharger and buy GEARS instead! If you want to shred tires (like a SC can do) then spend just 10% of a SC cost and choose a 3.73 gear instead. Unlike a SC, the car slows faster, too. Unlike a SC, the trans now has SIX daily-driver gears. Unlike a SC, you wont be fighting ignition or octane concerns down the road. You wont be able to hit 185 mph but you can get to 140 about as fast.

But CHOOSE A 3:55 for manageable wheelspin, cooler trans, cooler diff, and 165 mph, and 6-speed functionality.

If you have or plan HP upgrades above 600 or so, choose 3:33. Some say 3:45, but the metalurgy is not as strong at handling torque. PS I agree w/ Joseph... 355 in a Gen 3 feels like a 373 Gen 2, or a 411 gen 1. 355 is pretty much all-around-ideal, and dont choose a gear for the 1300 - 1320' mark of a drag strip if you dont plan to win $$ there most weekends. Gear you car for 95% of your driving, not 5%.

[ PartsRack has them ALL, at the best prices too. Thanks ]

I agree with most of this, but not the part about getting to 140 about as fast as a SC car. With a 5 pound Roe blower, I will get to 140 several seconds faster than a stock GEN III '3:55 geared' Viper. There would be absolutely no comparison. In fact, a stock geared 3:07 GEN III Viper will get to 140 faster than the 3:55 car because the 3:55 car will be in overdrive when it gets there and the stock Viper will still be pulling hard in 4th. I also have no ignition or octane problems after 22,000 SC miles.

Gears are a great way to go, along with a lightweight flywheel. I have both 3:45s and Fidanza flywheel to go with the blower. I did both before adding the blower and think it's a great bang for the buck. I use 6th gear all the time and can still get over 23 MPG at 72 MPH or so. I've found that most of the gear SOTP gain is in the first 2 gears. As the speed increases, the lower gear sets are compromised from stock due to the stock set pulling hard to 150+ in 4th, while geared cars are in a .74 OD gear above 125 MPH or so for 3:45/3:55s........but for getting the jump on the street, you can't beat them.

I do have a question about the statement that the metalurgy in the 3:45s is not as strong? When I bought my Unitrax complete assembly 37,000 miles / 3 yrs. ago, Devin told me that, of the gear sets he sold, the 3:45 was the toughest one. Has this changed? I've had zero issues with mine either on the track or smoking up a set of tires per year (both straight line and quite a few donuts)

By the gear calculator: A 3:55 gear set on a GEN III with 27.4" OD 19" MPS is equivalent to a 3:23 gear set in a GEN II car with 26.1" OD 18" MPS

Steve

 

[JonB]

........I do have a question about the statement that the metalurgy in the 3:45s is not as strong? When I bought my Unitrax complete assembly 37,000 miles / 3 yrs. ago, Devin told me that, of the gear sets he sold, the 3:45 was the toughest one. Has this changed? ...Steve

It changed in about 2001.......Ill try to get a 345 vs 355 Super photo posted, but side-by-side you can IMMEDIATELY see the more substantial set vs 345. Devin-Unitrax almost certianly cryo-hardened and polished the 3:45....making it an absolutely strong gearset, (originally built for vette racing) and is not likley to break.

 

[Hamrhead]

If you have a Gen3 you do not have to recalibrate the speedometer. It is done thru the tire low pressure sensors.
I was going to pull the trigger on 3.55 last week but my installer has talked me into installing a Quaife differential at the same time. I guess he knows my abusive nature and was told by Unitrax about the common failure of the stock unit.

I also spoke with Devin about the Quiafe, but decided I really have no plans on being quite that abusive. If I was a serious racer it would be something to consider, but for me the occasional trip to the strip will be as tough as it gets. (2-3 times per year)

Otherwise, Devin told me the stock rear should hold up very well.

 

[jk]

If you have a Gen3 you do not have to recalibrate the speedometer. It is done thru the tire low pressure sensors.
I was going to pull the trigger on 3.55 last week but my installer has talked me into installing a Quaife differential at the same time. I guess he knows my abusive nature and was told by Unitrax about the common failure of the stock unit.

I believe the Gen 3 use the ABS sensors to derive speed indication.

 

[CrimePays]

Any of you guys with the lower gears into drag racing. I am looking to speak to somone running low 10's that has gears in a Gen II that could share their 1/4 mile speed and rpm and what gear you finish the 1/4 in.

 

[JonB]

It changed in about 2001.......Ill try to get a 345 vs 355 Super photo posted, but side-by-side you can IMMEDIATELY see the more substantial set vs 345. Devin-Unitrax almost certianly cryo-hardened and polished the 3:45....making it an absolutely strong gearset, (originally built for vette racing) and is not likley to break.

CHAD: Please post the PHOTO HERE !!! 345 on left, 355 on right.

 

[V10SpeedLuvr]

It changed in about 2001.......Ill try to get a 345 vs 355 Super photo posted, but side-by-side you can IMMEDIATELY see the more substantial set vs 345. Devin-Unitrax almost certianly cryo-hardened and polished the 3:45....making it an absolutely strong gearset, (originally built for vette racing) and is not likley to break.

3:45 on left, 3:55 on right:

You must be registered for see images attach

 

[Hamrhead]

3.55's are now officially 'broke in'.

I've been out driving the car just about every night this week to get it done. Had to get some gas first thing tonight and managed a stellar 13.3 mpg. Then I decided to open it up.

First gear seems to dig in pretty well, but I do have PS2's. Feels gooood!! Besides that, it's gone real quick and ya gotta shift to 2nd, which now feels almost like 1st used to. Without powershifting (which I really don't care to do), I chirped the tires into 2nd and 3rd. 3rd gear winds out at just about 100mph now.

Not sure yet just what mph 4th will redline at, but I'll have plenty to get through the 1/4.

As of now my mods are 3.55's, Green Filters, DC Tune, and PS2 Tires. Corsa is in the basement - That's next. Probably wait until September/October to hit the strip.

 

[RTTTTed]

When I went for a test drive in a slightly modded (n/a)96 Viper with 3:55's the owner never even put the car in first, he said it was a useless gear. He did say that reverse was easier to manage though.

The first Viper I bought was a 98 GTS with 3:08s, a Roe 8#, water/**** and exhaust. It would smoke the Gen III tires at any speed under 100mph, not good and difficult to control. The last Viper I bought (01 GTS) has a Roe 10#, cam, rockers, Belanger, exhaust, filters (720rwhp) and went 10.5@139mph with Michelin Sports on it. It had 3:55s, but they went slower so the 3:08s went back in. Stock diff with Unitrax half shafts.

I did go for a drive in 1 stock Viper and it definitely needed gears of mods as it wasn't very fast.

I always drove both sc'd Vipers on the highway in 6th gear and got 21 & 20mpg (us). Speed I travelled didn't seem to make any difference to the mileage (50-100mph). The Roe superchargers make big hp & tq at low revs. 100mph = 2000rpm.

Ted

 

[black mamba1]

I see all the emphasis on gear upgrade. I am not sure I get this. John Hennessey's 587 rwhp Viper went 10.76 w/ stock gearing in the 1/4 mile in Motor Trend on an 03 SRT, whereas a guy in here only manage 10.5 w/ 750 rwhp w/ 3:55's. Do we really have such little confidence in Chryslers gear selection for track use? It seems to me the stock gear and higher hp is the way to go...lower gears amount to higher torque, something the Viper definitely has plenty of.

 

[dave6666]

I neither drag race or road race my GTS, but I have to say I like the fact that I can do 59 mph in first gear, 88 in second, and so on. My vote: 3.07 Add more goodies to engine if you want better response off the line.

 

[FE 065]

I just ordered a 3.55 Dana from a local company...Only $175 for the r&p, another $125 to install it if I take the diff down to them.

$300 total OTD ready to ROCK

--------------------------
1999GTS/2001 ACR
New SVS short shifter for sale

 

[Hamrhead]

I guess it all depends on How Much more power you plan to add.

For me, my plan was to keep it simple - Basic bolt-ons and that's it.

Stock, my car ran 11.90 @ 122.34, going through the traps in 3rd gear and touching the rev-limiter.

I figured if I added any more power, I'd be using 4th gear to get through the traps, but I wasn't adding enough power to make much use of it. So 3.55's only made sense to me. Now I can take better advantage of 4th gear being as I'll shift into it and still have some distance to cover before I go through the finish line.

Now my car has 3.55's, Green Filters, DC Tune/170 T-stat, and Corsa Track. On the street, it's definitely quicker, more fun to drive, and still hooks decent in 1st (And a bit cooler with the new exhaust). It's also much easier to drive slow when needed. Two of my friends have '04 Vipers, which are basically stock, and they're impressed with the way mine moves, but I guess the big test will be the strip. I plan to go when the weather cools off a little more - Hopefully September/October. Honestly, I don't expect much more trap speed, if any, but I do hope to cut a few tenths from my stock ET. 11.50 would be nice. We'll see...

 

[JonB]

I just ordered a 3.55 Dana from a local company...Only $175 for the r&p........

PartsRack and Unitrax 7-8+ years ago had 'dana' sets at $169. There are 36+ such broken sets in a bin at Unitrax. One of em was in my 1993. It could not handle 425 HP. Made in Mexico or China, we could still offer them at $175. We choose not to. We made good on all trade-outs and have not offered that 'stuff' since 1999.


YOU GET WHAT YOU PAY FOR..... best of luck. If the gear puts you into a wall, it is very expensive.

 

[FE 065]

PartsRack and Unitrax 7-8+ years ago had 'dana' sets at $169. There are 36+ such broken sets in a bin at Unitrax. One of em was in my 1993. It could not handle 425 HP. Made in Mexico or China, we could still offer them at $175. We choose not to. We made good on all trade-outs and have not offered that 'stuff' since 1999.


YOU GET WHAT YOU PAY FOR..... best of luck. If the gear puts you into a wall, it is very expensive.

I'll keep it in mind. Better yet, I'll quiz them on it tomorrow.


This company does enough gear & diff business (that's all they do) the current turn around time is 3 weeks-even if I bring the diff down. They're saying maybe mid-Sept I can hope for a 2-3 day turn around on my install.


Same place did my similarly priced 3.73 install 10 yrs ago with no problems while I had the car, and at that time they volunteered were doing JH's diffs from TX, as well as Corvette race team stuff.


Not like it's some little shop getting by on importing stuff from www.Made-In-China.com it'd seem.


When I called to check on the order a few days ago, he said the order had been placed with Dana and was still waiting on it. I actually thought it was like a Richmond gearset or the like.


So far I can't find anyone on the internet complaining about the company or what they sell..

--------------------------
1999GTS/2001 ACR
New SVS short shifter for sale

 

[PhoenixGTS]

...lower gears amount to higher torque, something the Viper definitely has plenty of.

My bolt-on only car (some of us cannot afford to flush $10k-$30k on another couple hundred HP) is WAY easier to "pedal" with short gears. With the ridiculously tall stock gears, once the rear tires started spinning - forget it - kind of like a fuel dragster. Run over. But with the short gears some how you have actual throttle response earlier and throught the spin (I think it is because the spin occurs at a higher rpm so when you let off you get a more pronounced downward effect on revs/power/spin). And of course totally on the other end of the spectrum, driving 0+ mph in a parking garage is so much nicer with short gears.

 

[FE 065]

The vendor says that Dana now owns a factory in Mexico that previously Precision Gear had gotten r&ps from in the 8yr or so ago time frame. Dana also has various other factories outside the USA.

To his knowledge, if a vendor order 3.55 gears from Dana, there isn't one Dana factory where good sets come from, and another factory Dana where bad sets come from.

The factory location may be mostly determined on what numerical gear sets a particular factory is assigned to make.

I've tried to contact Dana about more info. The holidya and myriad of Dana divisions may be slowing response down.

My vendor says there haven't been any reports from the field of any of the Dana gear sets made in Mexico failing. He says if anything, it's the Dana 44 itself, and the Viper aluminum case are more prone to failure..

 

[PhoenixGTS]

Great comments from SRT engineers apparently made during online discussion September 19, 2007 - as reported by Nader over on the Gen III board:

Apprantely 3.07 were installed to maximize fuel efficiency. They do elude to the fact that the car is geared too tall.

Engineer Quote, "If I were doing alot of "street/light competition" i"d use a 3.55 or 3.73. Remember nvh and fuel consumption will tank!"

FINALLY! Some real chatter from the horse's mouth to back up us short gear lovers! Especially interesting to hear the 3.73 number (equivalent to 3.55 on a Gen II).

 

[viperjim]

I still would go with 3.42 except the are not as strong. So I am stuck between 3.33 and 3.55.

 

[PhoenixGTS]

I still would go with 3.42 except the are not as strong. So I am stuck between 3.33 and 3.55.

Since you have the taller rear tires on your Gen III 3.55s would be like a 3.33 on a Gen II if that helps you compare a Gen II you have test driven or heard comments from the driver. Why are you afraid of the shorter gear?

 

[99 R/T 10]

I have a brand new set of 3.73's. If anybody is interested, PM me. They would make a great upgrade to any bolt-on Viper(Gen I/II). No so much for the boosted cars though

 

[Dawg2Snake]

I have logged about 500 miles since doing the 3.55 gears. I love them!! 1st is still functional, but a lot more torquey feel to 1st and 2nd. 5th and 6th are now functional. NO regrets!!!

 

[viperjim]

I have logged about 500 miles since doing the 3.55 gears. I love them!! 1st is still functional, but a lot more torquey feel to 1st and 2nd. 5th and 6th are now functional. NO regrets!!!

At redline in 1st what mph?
I believe at 80 mph in 6th I'm turning 1500. What do you turn?

 

[john cornish]

Help, I am having fun reading "Gear talk", but what should I do i have a 99" Silver Snake" High flow cats" K&N...(mostly stock)...I want to be faster out of the hole with some good top end. Which way should I go and what is the cost savings vs the Roe SC...
BIG JOHN
"MEZMERZ"
904-210-9947

 

[Dawg2Snake]

At redline in 1st what mph?
I believe at 80 mph in 6th I'm turning 1500. What do you turn?

3.55 gears from partsrack -
redline in 1st gear: 48 mph
80 mph in 6th: 1700 rpm

 

[Hamrhead]

I have logged about 500 miles since doing the 3.55 gears. I love them!! 1st is still functional, but a lot more torquey feel to 1st and 2nd. 5th and 6th are now functional. NO regrets!!!

I've done a little more than 500 by now on my 3.55's and I love them as well!

FWIW, now 3rd gear winds out about ~100mph. 4th will do about ~140.

6th gear is great now too! I can run it at low as 50mph, and now I don't have to downshift for grades on the highway - just keep cruisin'...

When the sun is out and the blacktop is warm, 1st gear digs in and I'm g-o-n-e, but now I have to be even more careful when the weather turns cooler. I pulled away from a stop sign the other night (about 60 degrees @ midnight), gently shifted to 2nd gear, accelerated to 45mph, pushed the pedal to the floor and the *** end kicked out. I was ready for it so it was no big deal , but you really need to be aware when 'playing'.

 

[Canyon707]

What ever happened to Made In America. 2004 Running 3:73 Mopar gears so far so good. DC tune, K&N cold air, 170 thermostat, Corsa Track, B&M shifter, Sidewinder wheels, PS2 tires, (that was a big improvement) Thinking German quaife rearend and shocks but I can't lower it, won't get out of the driveway. I am very happy with this car and its street performance. dynoed at 450 rwhp and 480 rwt.

 

[Parisianviper]

Thinking German quaife rearend and shocks but I can't lower it, won't get out of the driveway.

Quaife is a British company, KW is german.