Halp! 6 speed 3rd gear grind
 

Just bought a msm stock, 100k old lady owned it. If im in boost 2nd gear and i cant find 3rd Ill either grind 1st or just lock out or maybe 5th. Ive searched everyone says synchro. My guess is its mounts, my old turbo miata had super miata mounts and turbo this one has 100k oem mounts. Someone please Tell me i dont need a tranny rebuild. Ive changed fluid gl5 synthetic and it shifts like butter any tests i can do. I dont have to rev match either so idk any other ideas befoee i throw the teeth rattling super miata ones? Car is immaculate all stock i seriously doubt this lady was banging gears. But fuck i dont want a rebuilt one, i want those mazdaspeed shot peened gears. I. Diddnt see big flakes on the drain plug either.

Is there any "slop" in the shifter when the car is in gear at a steady speed? Did you re-build the shifter when you did the fluid change? The shift turret bolts could be loose, or the shifter itself in need of a rebuild, both of those can make it hard to find a gear.

Keith

Sry delete

im about to put in a new nylon pivot ball thing and new boots at the shifter im sure they need them. There does not seem to be much slop in the lever while at speed, certainly feels like my old one..the only time it does not shift like butter is when i haull ass from 2nd to 3rd. I feel like the entine is twisting to the right during hard second gear pulls. Ill check the turret bolts. But is there any other tests i can do. Ive tried bringing the engine to 5k in 3rd gear and popping it in neutral till the engine idles and can jam it back in to 3rd no problem and i beleve thats a hard test on synchros, i can definetly hear a nice healthy whine as the gears are brought up to synch like i did on my old 6speed nb, is this an invalid test?

Ugh its the synhros for sure, if i just take it up to 5000rpm under no load, like just maintaining speed, engine not twisting and shifter firmly planted i go for a nice slow shift and i get a nice crunch, FML i love tranny problems fuck.

Pretty sure there are 2 or 3 6 speeds for sale currently in the classifieds.

im weary of used transmissions for some reason :( i hate having my car down

mazda comp mounts, es diff bushings, rebuild shifter + replace the nylon bushing in there with a brass one. If that doesn't work it's time for a new trans.

BACK FORM THE DEAD. ok i forgot to mention as soon as i got the car i changed all of the fluids to mobil one synthetic shit like a good miata owner should, good idea for a new used car but mobil 1 does not make gl4 fluid for our trannies, i used their gl5 shit just like the owners manual says i could and i got a horrible grind after the car reached normal operating temps.

Dude i have no idea what actually fixxed my grind but its GONE. 100% gone, i can hit peak boost up to redline and snatch the shit out of 3rd gear chirp the tires and no grind. I changed out the slaver cylinder with a new one, i put in that ford 20$/qt fluid and i put in some of those bad ass motor 70D mounts from 949 racing. Thanks every one for your help! i hope this helps others in the future. Im so happy you guys have no idea, i fucking love how this car drives, god dude a miata with a fucked up 3rd gear is NO FUN at all omg. I used to have absolutely no 3rd gear synchro action when the car warmed up, id have to like baby the shit out the 2nd to 3rd shift basically just rev matching it to get it into gear. The shit that makes no sense to me is how the fuck is only one gear affected, i kinda felt like 5th gear did it too but idk only rarely. even with the gl5 fluid i could shift quickly trough the other gears. But yea im so glad i dont need a fucking transmission, i just bought this car because my old cars transmission took a shit. when i discovered that 3rd gear grind i was fucking livid! But yea cheers to everyone, that ford trans fluid is nice too, smooth all the time, cold or hot. weeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee <3

Gonads and strife!

Keith