Hey I was wondering if any of you guys know the rear end ration on my 75 Rx4 sedan. It has an auto matic. I dont know if that will change things. I would like to change up to a series one or two rear 3rd member if its taller. Those are 3.909 according to Mazdatrix. They don't have any old school rear end ratio info though. Im not concerned about wether or not its a lsd or anything. The car with the auto doesn't have enough power to break the tires loose let alone just one of them. I just want to be able to cruise on the freeway a little better. I ran at 65 from Phoenix, Az to Irvine, Ca at 3,900 rpm ish. The caravan I was with kept passing me on the way there so that I had to make my stops short to keep up. To cruise with those guys I would have to run at like 4,400 rpm. Not a good thing to do for 7 hours straight. Especially being so far from my own personal junk yard. A.k.a. home.

 

Ausrotary has a few good huge threads dealing with interchangability and other stats. Here's the giant diff list

http://ausrotary.dntinternet.com/for...nsmission+list

There's another one for trannies and another for long-blocks and interchangability of accessories. If someone wants to dig through for the good FAQ's, it would make for a great sticky.

 

Forgive me for hijacking, please. I'll consolidate things later, but also found the following:

Mazda Transmissions:
http://ausrotary.dntinternet.com/for...pic.php?t=2735

Everything Weber:
http://ausrotary.dntinternet.com/for...ic.php?t=75611

Porting:
http://ausrotary.dntinternet.com/for...ic.php?t=47212

Aftermarket Transmissions:
http://ausrotary.dntinternet.com/for...ic.php?t=37224


This forum is easier to get around and all, but DAMN those Aussies have a lot of info!

 

I for one certainly dont mind. The more info the merrier

 

Wow thats a lot of info. Definately answered my question. I need a cosmo diff. That 3.6 diff would be nice. And it'd be a limited slip too. Yay!

 

3.65 was the one in my 76 rx4, now it a 2nd gen 4.1

 

Yeah Im looking for the taller 3.65. We're talking about the same 70's vintage cosmo right? How did you go about making the 2nd gen diff fit?

 

Simple, the complet 2nd gen suspension, or you can get a rear deff from a frist and chang out the carrer with the one from the 4 so as the axles will fit they dont have the same splins, I'm kind of doing that rie now for some one, yep I haven't taken one pic of the job

 

Uh... You are talking about putting independent suspension in my leaf spring solid rear axle 75 Rx4. Yikes. I dont wan't to do that kind of work to it. I want it to be pretty much stock. And taking a 3rd member apart and lining the gears up properly doesn't sound like fun either. I think I'm just going to swap in a complete 3rd member from a 1970's Cosmo. That should have the desired result with minimal work. Heck I could probably retain the stock drive shaft.