A little more fuel consumption.

Yes better acceleration.

I don't think you'd get much more noise, maybe a tad. 3.42's are stock in the 6 speed.

I've found some good, low mile used ones(complete rear differentials) on here for around 600 + shipping. Probably $4-600 for labor to swap it out.

I've found new ones for $12-1600.

 

Mine doesn't even go to first when I stop if I'm in 2. It'll start off in second.

 

Are you sure Aerovette ? I my opinion, it prevents kickdown when you put your foot way down. And if you go to a stop and then accelerate it'll stay in 2.

 

ow. Does it mean that you have ratios like a 6-speed but have only 4 speeds? Which one are missing?

 

exactly how i drive mine

 

My knowledge of Corvette a4s is close to zero, but a typical automatic being shifted manually will still downshift. I don't think it is possible to be at a dead stop and start out in 3rd for example. I am assuming the same is true for second. If I completely stop at a light and my shifter is in first, it will not go to second when I pull away. If I am in second at a stop, the car would start in first, shift to second, and then NOT go to third. If I am slow rolling and stomp it and I am in second, it will downshift to first, then upshift to second and hold until I select third. Perhaps the a4 is different.

 

I am not sure about this one. I'll try it in mine later. Why would it allow that in second and not third? If you are in third or OD, it does not start out in third or OD. I have downshifted "early" and until my speed drops, it will not go in to first. I have experimented more with my truck than my Corvette so I am making some assumptions, but general design of automatics is pretty consistant.

 

I had a '99 chevy truck that would start off in second when held in second, and it would not kick down.

My a4 is the same way. 3 operates normal, at slow speed it will kick down from 3-1. In second tho', it stays in second.

 

Shifting an A4 manually simply locks out the higher gear, not the lower ones, except for second gear which will allow a second gear start. But if you floor it, it will still downshift to first. Conversely if you leave it in third, it will start in first and run through second and third, locking out fourth (OD). All of this information is in the owner's manual.

A 3.42 final drive ratio in an A4 means that the gears you will get better acceleration and that in top gear (fourth) you will be turning at a higher RPM. This is a very common upgrade and a very satisfying change, giving better response. The fuel mileage and noise level penalties are almost insignificant compared to the better feel. It will really wake the car up!

Having the shift points and shift pressures altered through a "tune" gives more performance oriented experience to the A4. The 3.42 upgrade plus a sharp professional dyno tune will really enhance your A4.

 

I should say at the outset, driving an A4 in the US and driving it in Europe is like chalk and cheese. Like you I drive European type roads here in UK although we drive on the "correct" side of the road I drove my A4 for many miles around CA and NV including a road trip around Tahoe.

I have the same trouble as you. On the rural roads I find the car always wants to upshift. On the bends that's a pain and I don't feel in control. I normally drop a few gears to make sure it stays in the appropriate gear. If you do though, make sure you keep an eye on the gearbox temperatures. Overtemping the box is a bad thing!

I agree that the kickdown can be lethargic and unpredictable. Without active handling the car is not fun on the back roads unless you're totally on top of it and not slowed down by people "pottering around". But with European gas prices we need to keep a sensible head. $7 a gallon is not fun and I can adjust my spend instantly with my right foot

You can have the A4 recalibrated and those who have had the mod say it makes the car seem totally different. The tuner will change the shift points and make it more suitable to your style. It may reduce the life of the box though.

If you decide not to go that way, try dropping to 3 or even 2 on the back roads or whenever you want the performance.

I know how many mods you have made to comply with EU standards, so changing to an MN6, however desirable that might be, is not an option.

 

5 and 6. Autos have a lower first gear, a little higher 2nd, and 3rd gear is the same ratio as 4th in a manual. OD is almost the same as 5th in the manual. Check this out. Scroll down about half way.

The a4 has a stock rear gear ratio of 2.73 or an optional 3.15. With 2.73's, the manual is a little quicker. 3.15's even that out a little. 3.42's in an auto should make it a bit quicker than the manual. If I figured right, it should run about 400 rpms higher at highway speeds.

 

Me too.........

 

Very interesting information here. Thank you guys.

I confirm the gear box will let you start in second if you are in position "2". It is usefull for example under very slipy conditions (ice ans snow). I am not sure it'll kickdown to "1" if you floor. Or maybe at very low speed?

My vette is a European model so I had no changes to do. But for sure I can't change the gear box.

I will do the autobox remap but on a conservative way. No boosting the pressure too high. I just want to avoid that tendency to always upshift and the very aggressive kickdown when not expected. I also want the gear to do 4-3-2-1 when i decelerate. Not 4-1 as it does not.

My feeling is that the car is perfect for large straight roAd like in the us. In our more "rural" roads and our different driving style we need a different gear management, more rigid swaybars and maybe different tires.

Then we have the perfect car for nice driving (on the good side of the road).

 

The C6 or the Z06 swaybars are fit form function replacements. That will stiffen up the ride.

I already fitted Michelin AS ZPs but they're not available here in Europe. Way better than the stock tyres. Vredesteins may be available but they're not runflats.

As for the "good" side of the road, I guess I'm in the minority here.............

 

I ordered C06Z51 swaybars and I think I'll replace my rundlat by falken 452.
Then I'll get a gearbox remap.
Then I'll change my intake for ls6 manifold + callaway honker + 2001-maf (to go with my borla stinger catback)


do you think it'll do well?

 

Sounds perfect

I wish my wife would let me do the same

You may want to invest in a Z06 plug kit in case you get a flat

 

Well about wife, you noticed I only sellected non noticiable upgrades (well except borla).

I also read a qaife differential was a great addon.

And... This conversation about changing the gear ratio makes me wonder if it is the best investment : you keep a stock engine but dramaticaly improve perf. Maybe better than gaining 20-30 hp?

 

Don't forget money for a tune. When you change the rear end, you have to change the shift point parameters in the PCM. Otherwise, it won't shift correctly, and do some serious damage.

 

Thank you sir, I forgot to mention that.

 

Yes more RPM. If you are in 3rd and doing 75MPH your RPM with the following gear ratios will be:

2:73 = 2,730 RPM's
3:15 = 3,150 RPM's
3:42 = 3,420 RPM's

Not sure about top end, but how ofter do you need to drive over 170MPH?