FWD Ring Gear Diameters and other info please

Hi. Having trouble finding results in google searches. Can people share the diameters of the ring gear in their fwd trans and other dimensional info about the ring and pinions as they like? I'm visualizing some design ideas. Thanks!

A transverse engine doesn't use a ring and pinion, so you are roughly limited to Audi, Tercel, Tornoado and Vigor.

Well technically they do, they just aren't hypoid.

This information will generally only be found by disassembling transmissions and taking measurements.  Unlike a right angle drive where the ring gear dimension is fixed in diameter and changes in width, while the pinion changes diameter, a transverse type transmission will vary the diameter of both gears in order to change the ratio. So a 3.91 and a 4.88 gear for a VW 020 transmission will be much different in diameter.

I'm referring to these parts. If any of you have them laying on a bench and don't mind measuring them, I would much appreciate it. 

My car has one ring gear and two pinions. :)

In reply to DeadSkunk (Warren) :

What is it? 

In reply to TAB :

What is your goal?

There are two moving targets here: primarily the bolt pattern and register diameter, which will be transmission specific, and the diameter of the gear, which on a front drive trans will be dependent on the tooth count.

TAB said:

In reply to DeadSkunk (Warren) :

What is it? 

R53 MINI Cooper S. The Getrag trans has a drive pinion on two shafts, so one will be powered at a time, depending which gear you're in. The Getrag trans in a Focus SVT is the same system.

In reply to DeadSkunk (Warren) :

Thank you for sharing that info.  I look forward to researching that some more.

In reply to Knurled. :

Thanks Knurled. I'd like to build a database with CAD files for various mass produced parts for design assistance for a Franken-Car.  As examples, I purchased an Audi transaxle and Cadillac CV Half Shaft Assemblies to aid in measuring bellhousing bolt pattern and flange bolt patterns.  Rather than amassing a parts bin for purposes of measurement and leaving me penniless, I'd like to use community knowledge to first measure these parts virtually.  I have had some success with GrabCad.  Perhaps there are other resources I am not aware of.

That is not going to be of much use, sadly.  The pinion gear on a front drive trans is almost always doing double duty as a gear cluster support, so it is not something you can swap between makes.  I know VW 020s, and even within that single model of trans there are two different sizes of mainshaft, AND two different ring gear bolt patterns, so just because a gear ratio exists does not mean you can use them with the gears in your trans.  Most of them require 16v gearsets, some require 8v, it's a mess.

Such a database doesn't exist because the likelihood of being able to use a ring gear from one with the pinion gear from another is vanishingly small, not just for diameter but also tooth angle, pitch, and form.

A colleague just shared with me McMaster-Carr.  They've got CAD files for the parts they sell.  For everybody's information.  Thanks all for being active forum folks. :)

Here's a little sample, just an example.  The 2 gear set on the right represents a final drive pinion and ring gear.  On the left the three gear set is a potential design.  To accurately draw to scale would facilitate in desktop design.  Is it possible (even probable) that it won't work?  Yes.  Is it worth doing the design exercise?  I think so.