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Old 09-17-2008, 06:00 PM   #1
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Default Serious problem... not driveable. Help diagnose

Ok guys, here's the deal.

First off, the car set-up is as follows... It's a 1995 with a Hydra ECU, ACT clutch, lightweight flywheel, 550s RC, GT2860RS, Begi mani/ DP, and other stuff which really isn't important for this post. Also the tranny is stock.

I was working on my car at a buddies shop. (Taking the BEGI DP off to get a new bung plug. For some reason they decided to have the original one pointing towards the ground!?!?) So I was driving the car to the actual shop where my buddy was going to weld a new bung on.I was accelerating at about 1/4- 1/2 throttle through 1st, then 2nd, then 3rd and all of the sudden "BANG"!!! A really loud noise came from under my feet ( I felt it too) and all of the sudden I felt incredible vibration in my shifter. I was actually very close to my apartment(literally one minute) at the time and decided to just limp home. The car making a LOUD clunking noise the whole way.

I pulled in and parked the car. I could shift between gears just fine without any extra resistance or grinding. Whenever the car was sitting at idle "in neutral" you could hear the clanking noise. Almost sounded like something was banging against the transmission (hence me being able to feel the vibration through not only the shifter, but the entire car). I really wasn't sure what had happened.I looked at the DP to see if it was banging and it wasn't. I looked around to see if anything was hanging, came loose etc. and nothing appeared out of the ordinary. So I got in the car and tried to roll back out of the parking spot( just to see what happens). I push the clutch in and the clunking noise stops. Car is still in neutral. I let it back out and the noise starts again. I push it in and rev the motor up high and nothing.... not a peep.

I put it in reverse and roll back a little and the whole car shakes and the clunking noise gets extremely loud. I pull back forward. So I guess it makes sense that it would either be the tranny, flywheel, clutch? Similar things etc.? I guess I really won't be able to know till I have it towed to my buddies shop and we can really check it out. I don't have tools or legit jacks to really get under the car here at the apartment complex. I'm hoping it isn't anything too serious, seeing that I am a poor college student. This is my DD, so it is making things extremely hard (getting to and from work).

So let me know what you guys think.... sorry for the lengthy post. Was trying to include as much detail as possible. Thanks in advance guys.

Last edited by ak47bravo; 09-17-2008 at 06:22 PM.
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Old 09-17-2008, 06:16 PM   #2
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It sounds like you are on track to me. I blew a tranny in a 5.0 one time. It acted the same way.
Good Luck!
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Old 09-17-2008, 06:31 PM   #3
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Quote:
Originally Posted by ak47bravo View Post
Whenever the car was sitting at idle "in neutral" you could hear the clanking noise. I push the clutch in and the clunking noise stops. Car is still in neutral. I let it back out and the noise starts again. I push it in and rev the motor up high and nothing.... not a peep.
I'm with ToddCod. It's not the flywheel or clutch, it's the tranny.

With the motor turned off put the tranny in neutral and have your friends push the car while you listen for noises or vibration. Try the same with the tranny in the various gears but with the clutch disengaged. I'll bet you'll find something doesn't feel right; hopefully this will help you narrow things down.

Last edited by Thucydides; 09-17-2008 at 07:17 PM.
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Old 09-17-2008, 07:57 PM   #4
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sounds like missing teeth on the trans input shaft or diff ring gear.
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Old 09-17-2008, 09:47 PM   #5
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Thanks for the help guys. What baffles me is that is was just instant. There weren't any preliminary symptoms for anything going out. Also on top of that, I wasn't even pushing much power. It wasn't like I did a 6k dump. I'm probably running around 200 whp right now.

When the tranny goes out, is it instant usually? Tomorrow I'm going to try and check it out some more. Thanks for the help guys. I'm taking it up to my friends shop this Friday, so then I'll really be able to get down to the problem. Just trying to get a good idea of whats wrong before then.
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Old 09-17-2008, 10:45 PM   #6
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1) the car still moves
2) the clutch disengages

1 + 2 = almost certainly not the clutch

This seriously sounds like when my buddy chucked some teeth off the trans input shaft of his mustang. If the teeth have fatigued they can go at a significantly reduced load and with little/no warning.
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Old 09-18-2008, 02:18 PM   #7
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Reverse gear and/or shaft is busted. Probably the shaft end broke loose, and is wobbling around in there. Hope you didn't crack the case.
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Old 09-18-2008, 04:32 PM   #8
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I guess I'll know for sure when I get to take a good look at the car. What do y'all think the worst case scenario would be? Cost wise?
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Old 09-18-2008, 05:40 PM   #9
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I wouldn't even waste time figuring out what happen or why (unless it's visible outside of the case, like an input shaft). Just pick up a salvage unit and swap them out.
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Old 09-18-2008, 07:08 PM   #10
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I wouldn't even waste time figuring out what happen or why (unless it's visible outside of the case, like an input shaft). Just pick up a salvage unit and swap them out.
Yea, I was going to go pick up a tranny this weekend for it, from a pick and pull. Any specific problems or issues on the 94-95 miata's with switching a transmission?
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Old 09-18-2008, 10:13 PM   #11
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I've interchanged transmissions one way or another on anything from 90-99 and it wasn't anything that I couldn't easily make work, nor worth remembering... Stick with the 94-97 trans since it's got good synchros and the stronger front bearing brace.
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Old 09-19-2008, 06:19 PM   #12
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Baby's first 5-speed
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Old 09-20-2008, 06:17 PM   #13
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Update: The car doesn't shake or make any noise at all when moving "While the clutch is in" .... do yall think it would be the input shaft then?
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Old 09-20-2008, 06:29 PM   #14
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It's the transmission. Something in it died. No doubt. Buy a new (used) one.
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Old 09-20-2008, 06:50 PM   #15
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Quote:
Originally Posted by ak47bravo View Post
Update: The car doesn't shake or make any noise at all when moving "While the clutch is in" .... do yall think it would be the input shaft then?
I'm still voting input shaft.
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Old 09-21-2008, 09:49 AM   #16
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If he drops the transmission, looks at the external area, and shafts, and possibly opens that case up to have a quick look for anything out of the ordinary, it would be a lot easier than to play the autozone game of "jump to one specific conclusion." I would also spin the differential too to make sure for some reason it wasn't that.
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Old 09-21-2008, 01:19 PM   #17
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Honestly, I would have already gotten a transmission already, BUT the pick-and-pull closest to me is like an hour away. I don't have a decent jack/ stands and tools (all that **** is back home in Houston). I can get all these things from friends here, but I only have time to work on the car on the weekends. I had a bunch of B.S. come up so didn't have time yesterday. Also I called the pick-and-pull to ask them if they had any Miata's in their inventory. I found out they actually don't keep track of their cars, so it would be a luck shot.

I'm trying to find a transmission here in San Antonio from a 94-95 (preferably already removed). This sucks...
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Old 09-21-2008, 02:49 PM   #18
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Ouch, thats pretty weak man. Sorry your dd had to **** on you.. Guess its the way it goes.
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