Just bought a sweet '96 A4 vert. Only thing I don't like about it is the 2.59 rear. It's got to go. I'm thinking 3.73's. Isn't the overdrive ratio in the tranny a .7? If I've done my math right, that would put the rpm's in overdrive with the 3.73's the same as in drive with the 2.59's. On a 5 mile run the fuel eco difference in drive vs ODrive was about 2.5 mpg at 70 mph. Acceptable to me because the car won't get driven a lot of miles and a bunch of those miles will be at slower speeds. I'm assuming the converter is locked in D and OD?

Not planning any other mods except 1.6rr's, long tube headers, and a tune. I'm hoping the 3.73's will really wake the car up. Has anyone done this swap? How'd you like it? I was quoted $1500 parts and labor to do the swap. About right? Does the PCM control the speedo calibration? TIA

 

You are correct that the OD ratio is .7, I have a 93 A4 and like you didn't care for the 2.59's. Many on the forum advised the 3.73's for an automatic car so I bought a pumpkin and installed them myself. Huge improvement in low end performance, barks the tires on the 1-2 shift which it would not do with the stock gears. My 93 required changing both speedo gears in the trans to correct, your 96 can have the calibration changed in the PCM.
Over time I've decided the 3.73's are too steep for my taste and have since purchased a D44 with 3.45's, I will install it with a 9", 2800 stall converter purchased from forum member Pete K.
I hope the converter will retain the low end punch of the 3.73's and the gears give me back a better freeway cruiser, I'll let you know the result once the heat slacks off a little here in Florida.
You might want to try a converter first, either gears or the converter should make a big difference, together they will be impressive.
Another forum member JD'sWHITE93 uses 3.75's and a high stall converter, he loves the setup so it is a matter of taste. I prefer a little less engine RPM on the interstate. My car is not a daily driver so I don't really monitor fuel mileage, but mine seems to have dropped significantly with the 3.73's
Good luck whatever you decide, have fun!

 

My car came with 3.07's and I have driven quite a few with 2.59's. I think you'd be surprised how much difference just the 3.07's make. I'd see if I could find a 3.07 car to take a ride in and see if that's enough for you. Still get great gas mileage and breaks loose on the 1-2 shift with just a Hypertech firmness adjustment.

 

$300-350 for the Ring & Pinion- Bought online
$80-100 for a rear end rebuild kit- New bearings & shims-Bought online
$50-75 rear end fluids
$250-320 four new half shaft u-joints
$240 labor to change out gears if I bring the pumpkin in to the shop.
$920-$1085 if I remove the pumpkin myself.

 

(I think I have the same car)

 

For the A4, 3.07 isn't too bad.

I got a Dana 44 with 3.07 gears, and it is just what I want.


Tom Piper

 

My other vette (selling soon) has the 3.07. It's noticably quicker. My thought was that if I was going to go to the trouble of changing gear sets, I might as well go a little higher (numerically) than the 3.07. I thought about going a little higher on the 3.07 car, but never pulled the trigger. Trigger will definitely get pulled soon on the new one though. 2.59 ain't cuttin' it. Just a matter of how high to go.

 

Can someone post the factory codes for the different ratios available on the 96?

Thanks,

Jake

 

G92 is the performance axle, and I believe the only one available from GM was 3:07. There is also a production code, G44 - 3:07, GM1 - 2:59 and GU2 - 2:73. this is out of the 1990 FSM.

 

I switched my 2.59s to 3.54s and installed a shift kit. Made a big difference. I'm turning about 2200 rpms at 70 mph. I payed $750 for parts and labor.

 

You might want to try a converter first, either gears or the converter should make a big difference, together they will be impressive.
Another forum member JD'sWHITE93 uses 3.75's and a high stall converter, he loves the setup so it is a matter of taste.

that's cause I'm tougher than you

3.75s
Pull the rear yourself and you can cut that $1500.00 down to about $750.00 including u-joints. Talk to Pete K and get a 2800 stall and you won't believe it's the same car. 20mph rolling burnouts are fun

 

Give it time!

 

I've always liked the "pep" that the 3:54's brought to my '96 with auto. Mileage ain't great, but hey, it's a friggin' Corvette!

 

I will change my 3.75 to a 3.73 when I destroy the dana 36 until then let the 20mph rolling burnouts continue I don't run the highway much so it doesn't bother me.

 

That converter talk has me thinking....I'm thinking you guys are going to cost me more money! I may back off of the 3.73's to something in the 3.54/3.23 range and add a higher stall converter. Are the ones ya'll are referring to lock-up style converters? How much $? This might get ugly. Thanks (I think).

 

Yes, the only way to go is with a lock-up converter. You can sometimes find good deals on this Forums from guys who have decided to change converters for whatever reason.

So the cost will depend on the deal you can find; no hard-and-fast price here. Say, for example, I bought a 2500 stall and decided I now wanted a 3000 or 3500, I'd be willing to sell it for $100 or more LESS than the 2500 cost me. Just to unload it to free up some $$ for the new one I want.

Of course, if you want to buy one directly from the company, the cost will sky-rocket. Check with Pete K on this Forum and see what he has to say about them, he's our trans and converter guy.

Hope this helps.

Jake

 

So, if it's a lockup converter, it shouldn't adversely effect highway mileage? That sounds like a win/win.

 

I changed my 3.07 to a Richmond 3.75 gear set. I love it! The car is really fun to drive. It will chirp the tires during 1-2 and 2-3 gear changes. My freeway driving is limited, but around town mileage improved once I learned to keep my foot out of it a little.

I did all the work myself and it was not that expensive, although it was time consuming. My main expense was replacing the 3.07 ring gear carrier with a 2.59 carrier, as the Richmond gear is very thick and made for the 2.59 carrier. If you change your 2.59 to a 3.07, you will also need a new carrier, but a 3.75 will bolt onto your 2.59 carrier just fine.
Also, I pulled the 700R4 trans tailshaft and changed out the speedometer gears. If you have a lift, it is a pretty easy job.

One last thought, I wish I had spent the money/time on a Dana 44 instead.

 

What are friends for
Do both at the same time, it will be cheaper that way, since you have to pull the exhaust and the c-beam anyways to do the rear there will never be a better time to do the converter. A 9.5 converter with a 2800 stall will flat out kick ***. It's also roughly 15lbs lighter than the factory 12" unit and that's right off the back of the crank. The 3.75s might be good for a tenth over the 3.5X gears I would GUESS. Mojo has a 93 with a 2800 and 3.5X rears and his is quicker than mine
His car goes 12.50s my BEST pass is a 12.77


p.s. you will need tires too
If you track it alot sooner or later you will break the dana 36

Isn't this fun ????

A converter is $330.00 and up talk to Pete K.

 

I agree. Gears and a converter. I am very happy with my 3.54 gears and a 2500 stall converter.