Gears & Axles Driveshafts | Rearends | Differentials | Gears | 12 Bolt | 9 Inch | Dana

ring and pinion swap

Thread Tools
 
Search this Thread
 
Old Sep 21, 2014 | 02:03 PM
  #1  
george88gta's Avatar
Thread Starter
TECH Apprentice
20 Year Member
iTrader: (3)
 
Joined: May 2004
Posts: 366
Likes: 2
Default ring and pinion swap

I know this has been discussed a lot, but I need to make a quick decision on what to purchase. Car is an 02 Trans Am conv. Basically stock LQ4, pcm retuned and has traction control. Gets 20 mpg around town an 25+ on the highway. Plenty of acceleration for a daily driver with the original 2.73 gears. Posi is going and it is developing a clunking sound so I plan to rebuild a rear axle assembly over the winter and swap it in. This way I can keep the car mobile while I gather parts, rebuild,etc. I have a decent deal on a used rear end assembly ( complete) but it has 3.23 gears. Question is how much of a hit will I take on MPG and can I retune the PCM with my Tech II or do I have to send the PCM to a tuner?
Reply
Old Sep 21, 2014 | 02:18 PM
  #2  
redbird555's Avatar
TECH Veteran
iTrader: (14)
 
Joined: Mar 2009
Posts: 4,444
Likes: 9
From: Pompano Beach FL
Default

sounds like your city is pretty rural 20mpg in REAL city traffic isnt happening even on a full moon lol. anyway the 25mpg figure seems realistiic for hwy. With that said gears will help your "city" mileage out a bit at the expense of the hwy... although with a modest gear swap to 3.23's i doubt it will be noticeable really. the 3.23's are a pretty good gear so you'll be happy with those as they'll reall ywake the car up but i'm not sure if the tech II can do the change.... if anything you may just be able to swap in a stock 3.23 gear tune if your car is stock
Reply
Old Sep 21, 2014 | 02:26 PM
  #3  
george88gta's Avatar
Thread Starter
TECH Apprentice
20 Year Member
iTrader: (3)
 
Joined: May 2004
Posts: 366
Likes: 2
Default

Originally Posted by redbird555
sounds like your city is pretty rural 20mpg in REAL city traffic isnt happening even on a full moon lol. anyway the 25mpg figure seems realistiic for hwy. With that said gears will help your "city" mileage out a bit at the expense of the hwy... although with a modest gear swap to 3.23's i doubt it will be noticeable really. the 3.23's are a pretty good gear so you'll be happy with those as they'll reall ywake the car up but i'm not sure if the tech II can do the change.... if anything you may just be able to swap in a stock 3.23 gear tune if your car is stock
Yeah, I live in the "sticks". May even get blacktop next year. Just kidding, but it is rural, a few stop signs and maybe 2-3 traffic lights. No city blocks and stop signs around here. Anyway, I dont need any more acceleration, but if the swap isnt going to be a big hit on mpg, then it looks like going to the 3.23's will save me the expense of getting a new set of 2.73's. I will look thru the TECH II books, but I may just have the PCM reprogrammed by a tuner. They did a nice job programming for the LQ4 swap so I am comfortable with their work. Thanks for the response.
Reply
Old Sep 21, 2014 | 04:32 PM
  #4  
FirstYrLS1Z's Avatar
TECH Veteran
20 Year Member
Photogenic
Photoriffic
Active Streak: 30 Days
iTrader: (4)
 
Joined: Aug 2004
Posts: 4,218
Likes: 147
From: Euclid,Ohio
Default

typical real-world freeway MPGs for an A4
2.73 - 25.9
3.08 - 24.7
3.23 - 24.5
3.42 - 24.0
3.73 - 23.0
4.10 - 22.2
4.56 - 21.5
Reply
Old Sep 21, 2014 | 04:54 PM
  #5  
george88gta's Avatar
Thread Starter
TECH Apprentice
20 Year Member
iTrader: (3)
 
Joined: May 2004
Posts: 366
Likes: 2
Default

Originally Posted by FirstYrLS1Z
typical real-world freeway MPGs for an A4
2.73 - 25.9
3.08 - 24.7
3.23 - 24.5
3.42 - 24.0
3.73 - 23.0
4.10 - 22.2
4.56 - 21.5
Sounds like it isnt a big deal for a daily driver. Anyway, next decision is to try and reprogram my self or hire a tuner. Thanks for the info.
Reply
Old Sep 22, 2014 | 02:40 PM
  #6  
01ssreda4's Avatar
TECH Senior Member
15 Year Member
Photogenic
Photoriffic
Shutterbug
iTrader: (96)
 
Joined: Aug 2007
Posts: 24,241
Likes: 89
From: Turnin' Wrenches Infractions: 005
Default

3.23 if the deal is good, 3.73 if you are paying full price.
Reply
Old Sep 22, 2014 | 05:05 PM
  #7  
george88gta's Avatar
Thread Starter
TECH Apprentice
20 Year Member
iTrader: (3)
 
Joined: May 2004
Posts: 366
Likes: 2
Default

Originally Posted by 01ssreda4
3.23 if the deal is good, 3.73 if you are paying full price.
Deal fell thru, shipping was more than the cost of the parts plus a 4 hour drive. So back to looking. Thanks for all of the help.
Reply




All times are GMT -5. The time now is 02:23 AM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE