2.73 to 3.73 gear change...

[RICEATER94Bird]

For those who have done this conversion. I need to know the impressions you guys got from doing the swap: How much quicker?, How much more responsive?, and how bad of mpg loss?. because i have 2.73's and i feel that my car could be quicker off the line even though its still pretty quick.

[MunsonGTA]

like nike says... just do it!

[86FireBird]

like nike says... just do it!

I agree...you cant lose...you can only gain...unless you go too too big but 3.73 is fine for an automatic.

[Joe 1320]

I went from 3.23s to 3.73s and the difference was decent. From 2.73 to 3.73 would be a nice wake up call.

[Injuneer]

Think of it this way..... off the line, it will feel like you added 37% more rear wheel torque than you have right now...... Hopefully, you have some sticky tires

[Trash man]

do it, i went from 3.08s to 3.42s and i think thats the major reason my car was 1 second fast then stock(among other things) also dont forget since u have a 2 series carrier u gotta get gears made for the 2 series carrier

[Christopherrr]

all i have to say is

your car really really becomes alive! tip in the throttle is the rev and surge is instant! You loose a little bit of grunt the top, but the surge from the line amazingly different from 2.73s.

do it.

I lost +-2 mpg overall. Not bad...I still get 26-27 with a host of mods and a tune...

You'll have to do a complete carrier, ring, pinion swap...don't forget the ABS reluctor ring too. with a complete bearing, seal rebuild the rearend (suggested) you'll be set back about $800 with labor. At least for me.

[Trash man]

i thought u could just get the gears as richmond(i think) makes them for the 2 series carrier for GM 7 5/8 rears

[DJ Taso]

I went from 2:73 to 3:73. In 2 years I snapped both rearends. Whatever you do DO NOT get Richman! The 3rd time I went with a GM factory 3:73 and it's been 5+ years with no problems.

The difference is day and night. If you have A4 you will notice you will be reving higher. Since I have M6, that 6th gear does wonders on the highway. Only complaint I got is minor gear whinage.

[toddwirges]

I went from 2.73's to 3.42's on my 2000 vert by doing a full used axle swap over. I could handle the heavy lifting but didn't have confidence in doing a gear setup. I had some confidence in the used rear being quiet, and the entire unit cost less than $200. Buying gears + a new carrier is going to run you alot more than that, which is why the 3.42's become so attractive.

You also have to consider the cost of programming. Don't forget that.

I lost about 2-3mpg. I'm not sure how A4 LT1 guys are saying they get 26mpg with 3.73's, but that doesn't seem possible to me. No matter how you look at it, figure on losing about 2mpg. It doesn't sound like much but 30 miles less range on a tank can be a pain, especially on LT1 cars with the smaller tanks.

My 2.73 LS1 got about 24mpg, and now gets about 21-22 after the swap.

It launches much harder. 2.73's with 275's would struggle to do a burnout on stickier surfaces. 3.42's just burn, and I'm out of first before most people riding in the car realize what's going on.

If you use your car as a toy, it is worth it. Otherwise, leave well enough alone. The costs really add up, just make sure to consider all of the costs (parts/install/fuel economy/tuning) and if it is still attractive, go ahead.

Also realize your going to be running quite a bit higher rpm on the highway, so if you have aftermarket exhaust you could end up boomy in your cruising rpm. Not as much of a concern on LT1 cars though. They sound so much nicer.

[Performin Norman]

I too have done the 2.73 to 3.73 gear swap. Best bang for buck and seat of the pants I ever spent money on that 94 z28.

[1995TA]

dont fear the gear!!

[Wild Willy]

I did the same as another poster above- swapped a 3.42 axle out of a wrecked Firebird- have to be sure to get the correct, either 3-channel or 4-channel ABS- depends on whether you have traction control or not-
Went from 2.73 to 3.42, and took the aluminum driveshaft, too! Big difference, especially in an LS1 car, which doesn't make as much torque down in the low RPM's

I would consider going to 3.73's but this opportunity came along and I jumped on it- I used to run 4.10's in an LT1 equipped Caprice, but that barge was a lot heavier and harder to launch from a standstill. Every time you leave a stop light or merge into freeway traffic you will grin....

[LoudLT1]

went from 2.73 to 3.73 huge difference...95 Z28 A4
on highway at 60 it revs at 2,400 rpm not bad on gas milege..
went with GM Motive gears the best. do it once..
best mod for the cost...get a good shop tho.
eddie

[ConElite]

95 Z28 A4
on highway at 60 it revs at 2,400 rpm not bad on gas milege..

Dang that pretty high. I like going 75 at 1750rpm's.

Hmm im going to have to think about it now, I was considering the change.