Bearing Noise (Transmission)
 

So when I put in my new engine I also installed a tranny with a big question mark on it. It was a spare that a buddy of mine had laying around and he said it certainly had less miles than the one I had in at the time (it had 184k) and didn't grind a bit when he pulled it. I said what the hell and put it in thinking it wouldn't hurt anything.

The problem is that the bearing noise isn't going away. I kinda hoped that it just needed some nice synthetic lube to get worked into all the nooks and crannies after sitting for so long but now i'm not so sure. It might even be getting worse. Sounds like I have a damn supercharger and its really annoying.

Is it possible that it could be the pilot bearing that came with my mazda value clutch kit or is this just a ticking time bomb of a tranny?

I know my PPF alignment is off 'cause I have that deceleration grinding sound that happens after most miatas have a clutch change. I had the same sound before with the old tranny and but didn't have any of this bearing noise.

Other than the noise, the thing shifts like butter unlike my old one that would grind more than kids at a high school dance.

My tranny has been grinding like that for thousands of miles. I'm not worried about it one bit, because when it does break, it'll be cheap to replace. Besides that, it sounds kinda cool, like I have the FM straight cut gears :)

My 99's transmission is noisy. I idled the engine up to ~1200 and it goes away. Or right now I idle at 600 and it goes away. But 700-1000 it's very audible.

mine is whining now since I've been turbo. I'm pretty sure it's the sound of the gears crying...and dying.

Lube Tirade:

get a poylyolyoolllol-ester gear oil. I've driven a 120k mile car in extreme anger on a track and it shifter very well with Motul. TDR loves that shit too, and very few people put down as many track hours as Gary.

I ran mobil1 in my car and at 154k the 4th gear synchro started acting like a ------ on shifts from 4-3 at 5500rpm after 20+ track days in one year.

the motul m300 whatever gear oil is $20 per liter, which is fucking gay, but probably worth it if you track as much as "we" do. I know redline oils are the shizzle, but I don't like mt-90...I'd consider running their 75w90 though. BITOG loves Schaeffer gear oil (and RL), and I may end up running that, and its cheaper.

I know that when I put in fresh mobile1 in my car, the bearings hushed up for a while, but I'm pretty sure I sheared it out the M1 after a few track days because that trans sounded like a spur-box the last time I drove it.

Mobil 1 is what I put in when I did the swap. Maybe i'll try switching to something else in the future if it ever gets to that point.

I know (or think I know) how to fix the grinding sound, just too lazy. That sound has never concerned me though, really.

I noticed tonight while driving that 5th gear is the noisiest one of the bunch while accelerating past 60 on the freeway. Oh well, i'll just ignore it for now like I have been. I just dont want this tranny turning to a giant paper weight after I put my turbo goodies on.

so how are you going to fix it, or is that a secret?

M1 doesn't roll over the spinning stuff as well as the best of the best.

Aligning the PPF to 66mm from the frame rails. That is supposedly how to fix the grinding. Someone just made a new post about it.