Will I have to remove the axles from the hubs to get enough room to pop the axles out? Or can I get enought room by just unbolting the diff and cradle and lowering it?
Whats the easiest way to remove the rear diff? I am going to swap the 3.90 for a 4.10 rear diff. Thanks,

Brady

 

Hi Brady,

as per resident expert Steven "Genghis" Kan, choice number two is a distinct possibility

 

make sure you get the e-brake lines unbolted from the diff, that'll keep it dangling

 

 

When I get down there this Saturday Mr. Genghis will be able to tell me for sure.
Thanks,

 

Can you make the auto Companion flange work with the manual drive shaft? I think I read somewhere on here you can drill a new set of holes in it. Anyone tried anything like this? The auto driveshaft is 12mm longer maybe an aluminum spacer would do the trick?

 

i have a question, what are the pro's and con's of that diff??

 

Here I got this off a web site.

We also offer different final drive (rear end) gears for nearly every street/racing condition. Adjusting the final drive gear ratio on your RX-7 will alter the acceleration and top speed. You can think of it almost like a 10 speed bicycle where the lower gears let you accelerate quickly but limit top speed whereas the higher gears are hard to get started (poor acceleration) but net a high top speed. For manual transmission cars, the stock final drive gear ratio is 4.10 (3.90 for automatic). Going to a different gear such as the 4.30 found in the Japanese spec cars will result in faster acceleration and a lower E.T.

The table below is meant to be a reference between the different gear sets on manual transmissions. It is fairly accurate considering stock rear tire circumference but it is not a guarantee that your results will be EXACTLY the same.

Final Drive RPM
5th gear@
60mph Speed
7500rpm
1st gear Speed
7500rpm
2nd gear Speed
7500rpm
3rd gear Speed
7500rpm
4th gear Speed
7500rpm
5th gear
3.90 2375rpm 39mph 68mph 98mph 137mph 191mph
4.10 2500rpm 37mph 65mph 94mph 131mph 182mph
4.30 2625rpm 36mph 62mph 89mph 124mph 173mph
4.777 2900rpm 32mph 56mph 81mph 112mph 155mph

 

I still don't have straight answer for my questoin.

 

Yeah, I have 500 post.

 

I met Steve and he is a really cool guy, but I forgot to ask him.

 

BUMP

 

and a bump.

 

Someone has to know the answer to this.

 

You will have to unbolt each of the rear knuckles from the upper control arm and toe link, but you can probably leave the lower control arm attached. That should give you enough movement that when you pop the inner axle shaft loose, you can withdraw the axle from the differential on each side.

You will definitely need to unbolt and remove the ABS sensor from each knuckle and tie them up out of the way of harm before removing any of the suspension bolts. You should also disconnect the emergency brake cables from the rear calipers for more flexibility. Just slide out the C-clip retainer and unhook the cable.

The inner axle shafts are about 4" long (shown on the bottom in the picture below), so you'll need at least that much room to get them out. Dropping the differential won't do it.

 

At least I won't have to remove the hubs then.
Is the top axle in the pic an ungraded axle? I notice it is bigger than the bottom one.

Thanks for you reply.

Brady

 

1999-2001 Mustang Cobra.