3.55 Final Drive

[Gary Dawson]

For anyone with a mostly stock Viper with the 3.07 ring & pinion that is considering the 3.55... do it! It will wake up your car making it much more fun to drive. Will it make the car any faster zero to 60 or in the 1/4 mile, probably not but the seat of the pants feel on the street is awesome. It tightens up the ratios between shifts too. And 70 miles an hour in 6th gear only turns 1500 RPM so I might actually use 6th gear more often. Another plus is my speedometer was not effected like it is on many other ring and pinion swaps.

They say MPG will take a little hit but let's face it, if that was our concern we would be driving a Prius. And no matter how much I put my foot in it, it's still cheaper than feeding avgas to any general aviation airplane. I'm still working on the initial break-in of the gears but the few times I have put my foot in it have been remarkable.

Tip: Pick a tech that specializes in differentials. The tech that did mine has specialized in differentials for over 40 years and he has done 1500+ differentials in his career. It takes special tools and expertise to get it right so don't let a couple hundred bucks be the difference between a job done right and a disaster. I took my car in on a Friday afternoon and he had it done the following Monday afternoon so there is no reason to make it a drawn-out winter project. Yes it was a little more pricy than the prices floating around here but I am confident it was done right and it's as quiet as a mouse with no whine or noise of any kind. As you probably know, the later cars came from the factory with the 3.55 so it is definitely a step in the right direction.

BTW, I have a factory 3.07 set of gears in perfect condition with 23,000 miles for sale if anyone needs one.

 

[Steve M]

I can't speak for the Gen 3 crowd, but 3.55s are pretty much the ideal gear for the Gen 4s as well.

For 0-60 times, it's going to be a bit of a wash depending on how fast you can shift. With 3.07s, you can hit 60 in first gear - with the 3.55s, you'll have to shift to 2nd gear, which takes precious time. Regardless, you'll never realize any benefit unless you are willing to run a sticky tire. Based on my experience, a drag radial is required. On a prepped track with drag radials, I've seen 0-60 times as low as 3.03 seconds (with a 1-foot roll-out, 3.27 seconds without).

For the quarter mile, terms matter, so I'm going to be very precise with my wording. When I say faster, I'm talking about the vehicle speed through the traps. When I say quicker, I'm talking about elapsed time. Keeping those terms in mind, 3.55s won't make the car faster (i.e. your trap speeds will be about the same), but it can be 2-3 tenths quicker compared to 3.07s.

There's nothing special about rebuilding a Viper Dana Super 44 (see this if you are interested in a DIY: https://www.viperclub.org/vca/threads/viper-dana-super-44-rebuild-how-to-gen-3-4-5-2003-2017.678645/) - any shop that specializes in Jeeps should have the required tools/skills. What does make a difference is finding someone who is willing to get the pinion depth absolutely perfect. I've rebuilt two now for my own car - one with 3.73s, and one with 3.55s. In both cases, the difference between too deep/shallow and perfect was 0.001" on the pinion shim (for reference, a sheet of paper is 0.004" thick). Both setups were silent in terms of gear noise. Sounds like you found someone that was willing to do what it takes to make it right.

As for the speedo, no recalibration is required for the Gen 3/4/5 cars since they read speed off of the ABS sensors. For the Gen 4/5 crowd, the factory calibration may need a slight tweak depending on how they set up the windows so that the PCM can tell what gear the car is in (it's referenced for a few things that I can tell). If not, you'll end up with some deceleration fuel cutoff weirdness (so if you end up with some really loud popping on decel, that's probably why). The Mopar/Arrow PCM calibrations already take this into account, though.

 

[BoremViper97]

A guy in may area claims to have a few dozen Viper rear-ends sitting on a shelf at his place. And he offered me a 3.42 (three forty-something) ready to bolt in.
I've been thinking a lot about that.

 

[BoremViper97]

For anyone with a mostly stock Viper with the 3.07 ring & pinion that is considering the 3.55... do it! It will wake up your car making it much more fun to drive. Will it make the car any faster zero to 60 or in the 1/4 mile, probably not but the seat of the pants feel on the street is awesome. It tightens up the ratios between shifts too. And 70 miles an hour in 6th gear only turns 1500 RPM so I might actually use 6th gear more often. Another plus is my speedometer was not effected like it is on many other ring and pinion swaps.

They say MPG will take a little hit but let's face it, if that was our concern we would be driving a Prius. And no matter how much I put my foot in it, it's still cheaper than feeding avgas to any general aviation airplane. I'm still working on the initial break-in of the gears but the few times I have put my foot in it have been remarkable.

Tip: Pick a tech that specializes in differentials. The tech that did mine has specialized in differentials for over 40 years and he has done 1500+ differentials in his career. It takes special tools and expertise to get it right so don't let a couple hundred bucks be the difference between a job done right and a disaster. I took my car in on a Friday afternoon and he had it done the following Monday afternoon so there is no reason to make it a drawn-out winter project. Yes it was a little more pricy than the prices floating around here but I am confident it was done right and it's as quiet as a mouse with no whine or noise of any kind. As you probably know, the later cars came from the factory with the 3.55 so it is definitely a step in the right direction.

BTW, I have a factory 3.07 set of gears in perfect condition with 23,000 miles for sale if anyone needs one.

I really appreciate your post.
My biggest question is - does the gear swap make 1st gear somewhat useless? Is it just wheelspin? or do you find yourself starting off in 2nd gear a lot for convenience?

 

[Gary Dawson]

I am still in the break-in phase of the new gears so I haven't buried my foot all the way in 1st yet. But for what little horsing around I have done, 1st is a lot meaner and feels more appropriate for the car. Yes I'm sure you can smoke the tires by simply putting the pedal to the metal but that's part of the fun when young guys tell you to punch it at a stop light. Like one of the other members said, "It's all about sticky tires" if you want to put that power to the ground and convert it into motion.

One little plus for normal driving (if driving a Viper can ever be considered normal) is you can get the car moving in 1st gear by slowly releasing the clutch at idle without touching the go pedal. Then slowly ease in the power and start going through the gears. BTW, this is the best way to keep a wife happy when she is on board.

 

[BoremViper97]

I am still in the break-in phase of the new gears so I haven't buried my foot all the way in 1st yet. But for what little horsing around I have done, 1st is a lot meaner and feels more appropriate for the car. Yes I'm sure you can smoke the tires by simply putting the pedal to the metal but that's part of the fun when young guys tell you to punch it at a stop light. Like one of the other members said, "It's all about sticky tires" if you want to put that power to the ground and convert it into motion.

One little plus for normal driving (if driving a Viper can ever be considered normal) is you can get the car moving in 1st gear by slowly releasing the clutch at idle without touching the go pedal. Then slowly ease in the power and start going through the gears. BTW, this is the best way to keep a wife happy when she is on board.

Man I really want to talk to you after the gears are fully broken-in.

 

[JonB]

3:55 = "Poor-Man's Supercharger"

 

[2013GeeTeeS]

With a transmission 1st gear being 2.66 id think that 3.55-3.73 would be great. It's what I have in my other car and yes, it's easy to blow off the tires (if that's your desire) but first gear is definitely not useless. My Gen V has the 3.55 gears but the 2.29 gears, so not ideal in my view for fun street driving. I'd love to jump to 3.9 and swap the 5th/6th gears to include the .50 OD. I feel like the car would be much more lively and fun to drive.