C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Rear end gears

Thread Tools
 
Search this Thread
 
Old May 6, 2007 | 06:17 PM
  #1  
laydoutjimmy's Avatar
laydoutjimmy
Thread Starter
5th Gear
 
Joined: Jul 2006
Posts: 5
Likes: 0
Default Rear end gears

I recentaly bought a 1987 corvette rear for a custom project im doing.... However im unaware of what gears are in it. I was told when i purchased it, that everything was stock. I know there is usually a tag that says the gear ratio but it must of been ripped/taken off

Anyone have any ideas

http://www.streetsourcemag.com/issue...PM26481_tn.jpg
Reply
Old May 6, 2007 | 08:54 PM
  #2  
CFI-EFI's Avatar
CFI-EFI
Race Director
10 Year Member
 
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Default

You should have a "Service Parts Identification" tag on the underside of the lid to one of your rear compartments or your console lid. Look for an option code starting with a "G". Ignore "G92". Any other "G" code will designate the ratio the car was built with. Also the ratio that was installed in the diff at the factory is stamped on the bottom of the diff. As a last resort, you can jack up the car, turn both rear wheels through one revolution, and count the drive line revolutions.

RACE ON!!!
Reply
Old May 6, 2007 | 09:11 PM
  #3  
laydoutjimmy's Avatar
laydoutjimmy
Thread Starter
5th Gear
 
Joined: Jul 2006
Posts: 5
Likes: 0
Default

sorry bro i just have the rearend so as far as the console goes i cant do that but i never looked on the bottom so tomorrow ill go out and check that out there is a lable on one of the half shafts that has a bunch of numbers ill post that also
Reply
Old May 7, 2007 | 12:44 AM
  #4  
xrcrx's Avatar
xrcrx
Burning Brakes
 
Joined: Feb 2006
Posts: 1,098
Likes: 1
From: Webster Texas
Default

2.59 was standard. 3.07 optional, if it's a D36
Reply
Old May 7, 2007 | 01:48 PM
  #5  
CFI-EFI's Avatar
CFI-EFI
Race Director
10 Year Member
 
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Default

Originally Posted by laydoutjimmy
sorry bro i just have the rearend so as far as the console goes i cant do that but i never looked on the bottom so tomorrow ill go out and check that out there is a lable on one of the half shafts that has a bunch of numbers ill post that also
DUDE i didnt notice from your opening post that you didnt have the whole car there is no factory tag on either of the halfshafts so anything you find there is not original information the turning of the shafts is the most reliable way of finding out the true ratio in case it has ever been changed

RACE ON!!!
Reply
Old May 7, 2007 | 02:12 PM
  #6  
MikeC4's Avatar
MikeC4
Melting Slicks
 
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Default

Originally Posted by CFI-EFI
DUDE i didnt notice from your opening post that you didnt have the whole car there is no factory tag on either of the halfshafts so anything you find there is not original information the turning of the shafts is the most reliable way of finding out the true ratio in case it has ever been changed

RACE ON!!!
one-ups-manship on non-punctuated run on sentences totally knarly dude i sure am glad you are back to your old self CFI-EFI far out man

Reply
Old May 7, 2007 | 02:47 PM
  #7  
aboatguy's Avatar
aboatguy
Race Director
15 Year Member
 
Joined: Jan 2005
Posts: 10,641
Likes: 13
From: Slidell Louisiana
Default

On the C4 rears I've seen the gear ratio is engraved on the diff. If you clean up the rear and look hard you may seen the ratio. Here's what the numbers on a D36 look like. My D44 is similar:

Reply
Old May 7, 2007 | 04:28 PM
  #8  
CentralCoaster's Avatar
CentralCoaster
Team Owner
 
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Default

Mine didn't have numbers on the casing.



I would check it by turning the pinion until the axles make a full revolution. If it turned 3 times, you've probably got a 3.07, etc.

If nothing else you can pull the cover off, on the ring gear the ring and pinion tooth counts are on there.

Like 40 13 etc. 40/13 = gear ratio.
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-1

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-2

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-3

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-4

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-5

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-6

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-7

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-8

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-9

2027 Corvette vs The World: Every C8 vs Its Closest Competitor

 Joe Kucinski
Old May 7, 2007 | 05:38 PM
  #9  
AKS Racing's Avatar
AKS Racing
Safety Car
10 Year Member
 
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
Default

For '87, the factory ratios were:

auto (D36)
coupe - 2.59 or performance ratio of 3.07
convertible - 2.73 or performance ratio of 3.07

std (D44)
coupe or convertible - 3.08

I am going by memory, but I think the above is correct. I hope you know whether the car was coupe or convertible, and D36 vs D44 is easy enough to determine. If all else fails, count the rotations of the input shaft (drive shaft) as a complete rotation of the output shafts (connect to half shalfs) is done.

Aaron
Reply
Old May 7, 2007 | 07:01 PM
  #10  
MikeC4's Avatar
MikeC4
Melting Slicks
 
Joined: Oct 2004
Posts: 2,510
Likes: 4
From: Austin Texas
Default

Originally Posted by CentralCoaster
If nothing else you can pull the cover off, on the ring gear the ring and pinion tooth counts are on there.

Like 40 13 etc. 40/13 = gear ratio.




Reply
Old May 7, 2007 | 08:31 PM
  #11  
laydoutjimmy's Avatar
laydoutjimmy
Thread Starter
5th Gear
 
Joined: Jul 2006
Posts: 5
Likes: 0
Default

well i have the rear end completely torn apart and the center section on jack stands. However i didnt feel like flipping it over so i just turned it, I turned the pinion one complete time and the half shaft turned about .4 of a a turn....

Any ideas fellas?
Reply
Old May 7, 2007 | 08:44 PM
  #12  
CFI-EFI's Avatar
CFI-EFI
Race Director
10 Year Member
 
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Default

that equals a ratio of 1:.4

RACE ON!!!
Reply
Old May 7, 2007 | 08:52 PM
  #13  
Z06_BluByU's Avatar
Z06_BluByU
Race Director
20 Year Member
 
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
Default

1/2.59=.386---> +/- .4

You have a 2.59 gear ratio set..
Reply
Old May 7, 2007 | 09:06 PM
  #14  
laydoutjimmy's Avatar
laydoutjimmy
Thread Starter
5th Gear
 
Joined: Jul 2006
Posts: 5
Likes: 0
Default

Originally Posted by 383_BluByU
1/2.59=.386---> +/- .4

You have a 2.59 gear ratio set..

Alright bro thanks.... whats a good set of gears to go with for jsut street cruising

Im actually putting this rearend in a 1995 gmc jimmy body dropped on 22's it has the stock 4.3v6 with a the heads cut down .020 and headers

I know it aint a ls1 or ls6 but im only 19 and on a budget hahah
Reply
Old May 7, 2007 | 09:08 PM
  #15  
laydoutjimmy's Avatar
laydoutjimmy
Thread Starter
5th Gear
 
Joined: Jul 2006
Posts: 5
Likes: 0
Default

heres the rear after i got done with it last night
Reply
Old May 8, 2007 | 12:43 AM
  #16  
CentralCoaster's Avatar
CentralCoaster
Team Owner
 
Joined: May 2002
Posts: 24,337
Likes: 25
From: San Diego , CA Double Yellow DirtBags 1985..Z51..6-speed
Default

Originally Posted by laydoutjimmy
Alright bro thanks.... whats a good set of gears to go with for jsut street cruising

Im actually putting this rearend in a 1995 gmc jimmy body dropped on 22's it has the stock 4.3v6 with a the heads cut down .020 and headers

I know it aint a ls1 or ls6 but im only 19 and on a budget hahah


What tire size? And what are your tranny gears? Need that info first.
Reply
Old May 8, 2007 | 08:01 AM
  #17  
Z06_BluByU's Avatar
Z06_BluByU
Race Director
20 Year Member
 
Joined: Nov 2000
Posts: 17,103
Likes: 39
From: stop the fun suckers
Default

with a jimmy i'm assuming an automatic.. the v6 is a bit underpowered compared to vettes.. I would guess you would be happy with a gear in the range of 3.45-3.73 (the lower getting more milage the higher having more pep..)

good luck!
Reply
Old May 8, 2007 | 10:46 AM
  #18  
sami85L98's Avatar
sami85L98
Le Mans Master
 
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
Default

pete k is selling 3.73 in sale section, it has new seals, spider gears and over all reworked, and everyone knows pete k he is damn good with these stuff, and the price is just right.
Reply

Get notified of new replies

To Rear end gears





All times are GMT -4. The time now is 05:01 PM.

story-0
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-1
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-2
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-3
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-4
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-5
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-6
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-7
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-8
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-9
2027 Corvette vs The World: Every C8 vs Its Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-24 16:12:42


VIEW MORE