Something is very broken
 

Hey guys, first post here. I need help, my 99 5sp has developed a pretty serious rattle, and at some points grind. It seems to happen when its warmed up but at this point it's pretty much from start up. Starts a little bit less intense but as I drive the car it gets worse. It sounds as if it is front left area and I can feel it in the floor boards. On rare occasion, it will feel like a grinding taking off in first until I'm off the clutch. It seems to get worse if the car is not level, facing up or down hill or in turns it seems to be slightly worse. I have gathered some info and I think it could be something in the transmission, a wheel (but a mechanic lifted the car and said the front end was solid?), the engine mounts, something in the exhaust, or a belt driven item (as the engine lugs a bit, gets a LOT worse, like something slapping around. I mean, I don't even know where to start.

Your 5 speed is fried. It is common with 5 speeds, and is why most people choose a 6 speed when making more power.

Are you kidding me? Oh hell... I mean I knew the synchros were on the way out because it is a little harsh into second and it clicks a bit.

If the trans is toast, is it easy enough to just drop a 6 speed in. Like legos?

yep, drops right in

Yep, or another 5-speed. They go from free-$150 or so. If you are making 250wtq or less that's what I'd do. If your engine is built, time to step up to a 6 speed.

Double post? I didn't even impatiently hit the button twice.

MT.net has been slow and buggy lately. At least for me...

I've been seeing a lot of doulbe posts lately though too, so can't just be me..

6speed is gonna be a bit of money, so unless you are making some power, no point in not just getting another 5 spd.

Check your crankshaft end play. The symptoms given are very similar to those of the dreaded #4 thrust bearing problem that affected 99-2000 models. I believe the rough spec calls anything less than .010in OK, but ideally it should be about .006in. If yours has the thrust bearing problem, you'll likely see a LOT more end play than that.

99 Miata thrust bearing failure

Hope this helps!

Says that it happens within 12-20k miles. Mine is almost 100k

Where do you go about getting a transmission for 0-150?

criagslist, or classifieds on forums like this.