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

Incorrect gearing

Thread Tools
 
Search this Thread
 
Old May 24, 2011 | 02:08 AM
  #1  
mattbm2001's Avatar
Thread Starter
Teching In
 
Joined: Apr 2011
Posts: 21
Likes: 0
From: San Bernardino CA
Default Incorrect gearing

I have a 1999 z28 m6 t-top Camaro. Shortly after buying the car I realized the speedometer reading was incorrect. I put my Garmin GPS in the car and got on the freeway to find that at the speedometer reading of 50mph I was almost at 65.

Using a formula I found on the internet I determined the rear end gear ratio is somewhere near 2.73, yes TWO seventy three. 6th gear at 70 mph is a mere 1200 rpms. I'm very familiar with driving manual transmissions so I can easily drive the car, but notice it is very difficult compared to most to get moving in.

While speaking with a friend of mine, not sure how credible his information is, he said something about using a rear end from a jaguar in it. I've never heard of this before so thought this would be the best place to ask such a odd question.

While we are on this topic my next question is, to go 3.73 I would need a new rear end, a "three series" rear end, is this also correct?

The rear end currently in my car does have some form of limited slip, I know there are many variations of limited slip or POSI rear ends, what kind did the 99 z28 use?

Another question is what width is the stock camaro rear end? I have a check coming to me in the up coming week or two, and would like to use some of the money I'm getting to get a more enjoyable gear ratio in my car. Any advice or responses are appreciated greatly. Thank you for taking the time to read this.
Reply
Old May 24, 2011 | 02:05 PM
  #2  
wfritts911's Avatar
On The Tree
iTrader: (2)
 
Joined: Jun 2010
Posts: 127
Likes: 0
From: Arkansas
Default

Sounds to me like someone blew the original 10 bolt which had 3.42s and swapped in the first 10 bolt they found which happened to be 2.73s. But on the bright side you could probably drive 100 and still get good gas mileage. As for the limited slip the 99s were the first year of the Torsen diff, google it to find out more info. As for the swap to 3.73s yes you would need a new axle or a thick gear set. As for the friend's jaguar rear end idea, im raising the bs flag.

-Will
Reply
Old May 25, 2011 | 11:38 PM
  #3  
mattbm2001's Avatar
Thread Starter
Teching In
 
Joined: Apr 2011
Posts: 21
Likes: 0
From: San Bernardino CA
Default

I agree on the BS flag. And yeah that was also my assumption about ending up with 2.73. Yeah, excellent mileage and lots of high speed cruising. I live in San Bernardino CA and have been looking for rear ends for that car and not many out there. I went through 5 different wrecking yards, and the best I found was a 3.23 with a nice tight posi. Figured it still a lot better than 2.73 and leaves the option of going to 3.73 later.

I bought it, was only 120 bucks. I have it outside right now prepping it for install. My question though, as far as gear oil and posi additives go, what are my best options?
Reply
Old May 26, 2011 | 12:12 AM
  #4  
mattbm2001's Avatar
Thread Starter
Teching In
 
Joined: Apr 2011
Posts: 21
Likes: 0
From: San Bernardino CA
Default

Scratch the previous question, upon googling torsen differential I found all the information needed. My new question though, according to the manufacturer website, there are two kinds. The better being the T-2R. I think the camaro uses the better of the two, the T-2R, it speaks of preloading to eliminate a problem with one tire coming off the ground. I would imagine that's what the springs are for? Please bare with me, I'm very new to all of this.
Reply
Old May 26, 2011 | 04:43 AM
  #5  
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

Buy a thick 3.73 or 4.10 gear set from Motive. Buy a master install kit. Go to a ring and pinion shop.
Reply
Old May 27, 2011 | 02:23 AM
  #6  
mattbm2001's Avatar
Thread Starter
Teching In
 
Joined: Apr 2011
Posts: 21
Likes: 0
From: San Bernardino CA
Default

Okay I've come across a problem. I yanked the 2.73 rear end from my car only to find a difference between it and the rear end I purchased. The one I bought at a self serve wrecking yard, came from an 02 TA. the 2.73 I pulled has disc brakes of course with the drum for the parking brake. The TA one does not, it uses the discs only.

I have both sets of calipers, and from what information I have found on the forum my car was suppose to have the disc with drum parking brake, but has anyone ever put the disc only setup in their 4th gen? If either will go in some what effortlessly, which one is better?
Reply
Old May 27, 2011 | 03:04 AM
  #7  
brianfromhawaii's Avatar
11 Second Club
iTrader: (3)
 
Joined: Oct 2007
Posts: 857
Likes: 0
From: Hawaii
Default

Why dont you just change out the ring and pinion?
Reply
Old May 27, 2011 | 08:45 AM
  #8  
Valkyn's Avatar
TECH Enthusiast
20 Year Member
iTrader: (8)
 
Joined: Mar 2005
Posts: 686
Likes: 0
From: Phoenix AZ
Default

If the rear dosent have the drum portion for the emergency break it may be an LT1 rear, they have the E brake built into the caliper.

Looks like this : http://shbox.com/1/rear_caliper.jpg
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

 Brett Foote
story-1

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-2

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-3

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-4

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

 Verdad Gallardo
story-5

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-6

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-7

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-8

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-9

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo




All times are GMT -5. The time now is 02:49 PM.

story-0
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-04 18:13:20


VIEW MORE
story-1
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-2
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-3
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-4
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-5
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-6
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-7
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-8
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-9
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