Prepairing to change out the rear end on my 84-Z, (3.23) with a car of the same year same trans and motor. Not sure of the gear ratio. Any advice and knowledge would be gratefull. Thanks guys
Spenc

 

Why are you doing this? (a little history is often very helpful to understanding the situation)

The VERY FIRST FOREMOST AND IMMEDIATE THING to do, is to pop the cover off of BOTH rear ends, and LOOK AT WHAT'S INSIDE OF THEM.

Determine the gear ratio of what you have now, and what you're putting in. Determine if what you're taking out is/was a posi, and likewise for what you're putting in.

Pop the axles out. Determine if the place the bearings ride on them (they're the inner race) is any good.

Determine what brakes you're taking out (drum, disc) and what brakes you're putting in.

Note that there's ALOT of inspection going on here. Not, "assuming"; not, researching "codes"; not, posting on the Internet; we're talking about INSPECTION. aka looking at the parts.

Come back and tell us what you see. Post photos if you don't know what you're looking at and we can help you figure it out.

 

Thanks soakingdom for your reply. I've owned this Z for over 20 years and added over 200,00 highway miles in it. At an intersection I had to cram reverse and gas to avoid being part to an accident. Wheels hopped and I saved the front end damage but now have twisted axles and broken teeth. I know my gears are 3.23 ratio. Can't afford the $1600 for a rebuild so thinking about going after a rear end from another '84' with same trans and motor.
Problem might be that I won't be sure of the ratio. Well pop the cover for inspection. The next question can I still roll with a 3.42? 70 year ole cruzer not to worried about millage. Spenc

 

You can use any ratio you like. People change them all the time. If you get a 3.42 it's going to increase your freeway RPM a little bit but not a huge change from 3.23.

If you get the speedometer gears from the 3.42 car and swap those in as well it will display correct speed.

GD

 

get a wire brush and brush down the front side of the axle tubes, one of them (I cant remember which one...i want to say drivers side...but i'm not 100%) will have a 3 digit code(a letter and 2 numbers) that will tell you what ratio THE FACTORY installed and weather or not it had posi, the chilton manual will have a breakdown I would look it up for you but i'm deployed and my manual is at home, i'm sure someone on hear wouldn't mind looking up the code, from there you can figure out the speedo gears you need to make the speedo read correctly. remember...this is what the factory put in it....all bets are off if someone messed with it