Its become apparent that my memory isn't quite what it used to be.

Story time:
About 12 years ago, I had some excuse to pull the differential out of the car. While I had it out, I checked the rear axle ratio. I've had it in my mind that the previous owner had swapped out the stock 4.10 for a manual, and put in the 3.90 ring and pinion out of an automatic. As I've had other things to worry about on the car, I didn't worry too much about it.

I saw an ebay auction for an 04 RX-8 differential with a bad housing, and figured now might be a good time to finally do something about the 3.90 gearing, as it was a nice cheap (compared to the $700 ring and pinion from mazdacomp) chance to do so. I'm not commuting in the car all that often, most of the miles this last year have been to, from, or at autox.

The ebay differential showed up on my doorstep Tuesday, as did the mazdacomp axle seals (left side was leaking, good chance to swap it out). Saturday morning, as kid is watching cartoons, and wife is napping on the couch, I figure I might as well get to work.

Opened up the RX-8 diff. Sure enough, 9 teeth on the pinion, 40 on the ring, for a 4.44 ratio. Remove diff from the car. Open it up, and get ready for the swap. Decide just for grins to do a tooth count. Pinion: 10. Great, I think...so the ring is only 39 teeth. I started counting. As I got to about 35, I realized I was an idiot, as there was still about 1/4 of the ring to go.

43.

denial - recounted 3 times, all came out to 4.30 gearing
anger - WTF!!!! How did I convince myself it was a 3.90?!?!
barganing - kinda skipped this one
depression - damnit, I just wasted my saturday, and $150 on this.
acceptance - well, at least I can fix the axle seal, and can probably sell the 4.44 gears for most of what I bought the diff for....

So...I've ordered a new set of diff bushings, so its not a total waste, but its not worth the realignment of the pinion / shimming / etc. to go from a 4.30 to 4.44.

TL;DR?

Anyone want a 4.44 ring and pinion for a decent price?

 

Not a complete waste, you can use the rx8 diff cover on the fd diff. It is a bit better for cooling.

 

Wow, I feel bad but I did laugh as I read it.

 

Haha good times! Yeah, not worth it to go to 4.44's from 4.30's, the difference is minimal.

You may want to recalibrate the speedo since you do have different gears, search for my writeup so you can have a GPS-accurate speedo.

Dale

 

Wanna sell the 4.30s ?

 

Unfortunately the cover has a broken fin, not sure it's going to be too much better cooling wise. I might do a side-by-side as I reassemble to see what looks like its in better shape anyway.

Don't feel bad...humor was most of the point of the post.

Definitely going to look that up...a little worried what it will do to my insurance rates though. I've been driving this car for 14 years now knowing the speedometer is ~5% fast...might not be a good idea to take away my "wiggle room". And yes, I should have realized that if the speedo is reading fast, I have higher gearing than stock, not lower, but I figured it was the previous owner trying to adjust to the 3.90 I thought was in the car, but not getting it quite right.

I'm keeping the 4.30s in the car, so I don't have to realign the pinion / etc. I'm already in PM's with someone about the 4.44s, if it falls through, and you're interested, we can talk about them at that point.

Travis