What is the approx cost to change to a 3:42 gear, I am looking to up grade my 02 to a 3:43 A4

Newt

 

Depends on a few things:

1. Are you going with a brand new differential or will you buy a used one? A new one will run about $1000.00. Used ones, I have seen for anywhere from $450-500.00. But as with any used part, you have to really trust the seller.

2. Where you live will play a role in terms of installation costs. My labor cost and costs for a few miscellaneous parts, such as diff fluids, anti slip additive, and items which the installer preferred to use instead of the supplied transmission cooler items, for the differential swap, the torque converter swap and the install of a transmission cooler was just over $900.00 after tax.

The quoted price for just the gears and TC was $750.00. But the 7% tax, tranny cooler install and nick nacks (for example, he didn't want to use the supplied hardware which came with the tranny cooler, he wanted to dbl clamp everything, etc, and I must admit he did a good job. These brought it to just above the $900.00 mark. $910.00 if I remember correctly.

3. Which option will you used for the required PCM programming following the gear change?

4. Will you be changing the torque converter too?



All of the above will affect the overall cost of a gear swap.

 

If I was to not add a TC would a 3.42 do the job for a little fun on the street or should I go for the 3.73?

Would a better option be to stay with my 3.15 and add a low stall TC. Driveabilty is number one. I use this as a daily with about 50 miles a day of highway driving and another 20 of in-town driving.

I am not looking for the fastest answer for the track, but something that will be strong from 0 to about 60 or 80 MPH on the street.

 

There is always more than one way to skin a cat. Or a snake


Either option would work if all you want is a bit more acceleration for the street. Each of the options you listed is a good option if that is your goal.

 

Will going from my 3.15 to the 3.42 make much difference without adding a TC?

 

Mike Mercury can answer this one better most. He did this exact modification and kept the stock converter.

I have driven a 2.73 geared C5, my own before my conversion, and a 3.15 geared C5, both with the stock converter and I noticed very little difference between the two. Me personally, I am less than impressed with 3.15 geared C5s. One man's opinion, but there does not seem to be a dimes worth of difference between the two.


I have never driven a 3.42 geared Vette with the stock converter. But my 3.42 geared A4 with ProTorque 2600 stall converter is head and shoulders above a 3.15 geared C5 with the stock converter. I have had the opportunity to compare the two.

My opinion is that if you will be going to the track, even on infrequent basis, the torque converter is a must. It doesn't have to be a 3600 stall. But the stock converter is only going to give you so much when it comes to 60 ft times, even with drag radials.

But as I said before, IMO, if you won't be going to the track at all, then no real need to change the converter.

 

the 3.15 to 3.42 upgrade is the least amount of change one can do on C5 rear axle ratios.... 8.6 %

I could instantly tell a difference in mine, but I am "sensitive" at detecting changes. Though the difference wasn't a day/night improvement.

Since many believe that the 3.42 ratio is as far as one should go when using run-flat tires... then this is one reason to upgrade from the 3.15.
My 3.42 with stock TC is at the very edge of EMT tire gripability. The car is still a "no-brainer" to drive. I can mash the gas pedal anywhere and anytime and the car still be controllable. Oh, I get a lot of wheel spin sometimes - but not so much that the car gets out of hand.

IMO; any more radical in gearing than the 3.42 or the addition of a higher stall TC would now require the driver to "think first" before every radical throttle increase... which is not what I personally wanted in my '02.

Of course if one is eager to replace the run-craps with conventional non-EMT tires, then that changes the suggested gear/TC upgrade limits.

 

Great info guys.

 

1695.00 Price is drive out including tax and re-programing.

Kevin

 

I recently went from 3.15s to 3.73s and am very happy with the results. 3.73 gears, a high-stall converter, and stickier tires create a hard to beat combination.

Also, long trips at highway speeds are not a problem with 3.73s. My A4 car's engine turns just 2600 rpm @ 80 mph in OD.