as you could tell i dont know crap about drivetrain. what is a drop out carrier and does the 98 z28 have one?

 

On most current GM rear axle assemblies, the carrier is held by two bearing supports that are part of the complete rear axle housing. To remove the carrier, you pull the back cover off, pull the axles outward, unbolt the bearing caps and pull the carrier, with the ring gear out the back. The pinion is still in the housing, and has to be removed separately. To set up the rear, or to switch gear ratios, you have to assemble one piece at a time, measuring the pinion gear depth in the housing, and then insert the carrier and concern yourself with the backlash. Not something you can do in a hurry.

A "drop out" carrier was used in very early GM cars (I had one on my 63 Impala), and on the Ford 9-inch rear axle. With that setup, the entire carrier, with ring gear and the pinion are mounted in the front cover of the rear axle housing. Drop the driveshaft, pull the axles outward, and the entire front cover/carrrier/ring/pinion assembly comes out. To switch gear ratios quckly, you have a spare drop-out section with your choice of gear ratio, already set up and ready to go. This makes it possible to change gear ratios at the track, an in hour or so (the torque arm mount of the 3rd and 4th Gens complicates the swap).

All 3rd Gens (except for a few that got 9-bolt Australian Borg-Warner rears) and 4th Gens used the 7.5/7.625" 10-bolt rear, which requires removing the rear cover, and disassembling the carrier/ring gear and the pinion shaft separatey. Not a "drop out".

If you buy a Ford 9-inch for your 4th Gen, you can use the drop-out section type rear.

Center section for a Ford 9-inch:



9-inch in a 4th Gen:

 

It's the only way to go if you change gear ratios a lot.
Can you imagine how popular(for those that had the funds) a 'quick change' rearend for f-bods would be.

 

I like my 9"- if I ever break it or need to change the gears I don't have to take the car to the shop and pay for labor to rip the whole end apart just to get to the gears when I can easily do it myself.

 

thanks that helpped alot.