How to properly replace rear axle with lower gearing
Thread Starter
Member
Joined: May 2010
Posts: 198
Likes: 0
How to properly replace rear axle with lower gearing
So how low is too low when replacing the rear axle ring and pinion?
Will I run into any issues on my 89 camaro rs 305 with 700r4?
Where can I buy a speedometer gear to match it?
I am just asking because I have replaced one before on a truck and they made a speedogear to go with it.
Will I run into any issues on my 89 camaro rs 305 with 700r4?
Where can I buy a speedometer gear to match it?
I am just asking because I have replaced one before on a truck and they made a speedogear to go with it.
Last edited by jay173; Jun 25, 2010 at 05:11 PM.
Joined: Jun 2002
Posts: 1,296
Likes: 6
From: Vancouver, WA
Car: 87 IROC-Z28
Engine: 305 TPI-New 355 on the engine stand
Transmission: T56
Axle/Gears: 3.73 Eaton posi-Soon a 9" Ford!
Re: How to properly replace rear axle with lower gearing
You need to post in the transmission and drivetrain forum, not the engine forum.
On Probation
Joined: Oct 2008
Posts: 6,319
Likes: 19
From: Northern Utah
Car: seeking '90.5-'92 'bird hardtop
Engine: several
Transmission: none
Axle/Gears: none
Re: How to properly replace rear axle with lower gearing
It's engine-relevant to ask what gear ratio is right for a pure-stock LO3. The speedo info does belong in the trans sub-forum. The answers are there, because I made the stickies. One on how to figure out what you need, another on how to get what you figured.
For a pure stock LO3, or even with external bolt-ons, a 3.42:1 gear is right, a 3.73:1 gear is too much. Do all the bolt-ons, plus cam and heads, then you might want 3.73:1. But better to just do the bolt ons plus 3.42s, then do a 350.
The best way to get 3.42:1 gearing is to get the complete rear axle assembly from any '90-'92 F-car with the V6 / auto. Then order a PowerTrax conversion-style locker. This way you don't have to worry about preload or backlash, or the stupid crush sleeve, and you get the 28-spline axles, and it's the 7.625" ring gear.
For a pure stock LO3, or even with external bolt-ons, a 3.42:1 gear is right, a 3.73:1 gear is too much. Do all the bolt-ons, plus cam and heads, then you might want 3.73:1. But better to just do the bolt ons plus 3.42s, then do a 350.
The best way to get 3.42:1 gearing is to get the complete rear axle assembly from any '90-'92 F-car with the V6 / auto. Then order a PowerTrax conversion-style locker. This way you don't have to worry about preload or backlash, or the stupid crush sleeve, and you get the 28-spline axles, and it's the 7.625" ring gear.
Thread
Thread Starter
Forum
Replies
Last Post
hectre13
Engine/Drivetrain/Suspension Parts for Sale
2
Dec 11, 2023 08:14 AM
