3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.
Sponsored by:

All gears grind/crunch.

Thread Tools
 
Search this Thread
 
Old 11-23-10, 11:06 PM
  #1  
Rotary Enthusiast

Thread Starter
iTrader: (4)
 
Aeka GSR's Avatar
 
Join Date: Nov 2004
Location: Riverside, CA
Posts: 1,086
Likes: 0
Received 2 Likes on 2 Posts
All gears grind/crunch.

I have a transmission that is sitting in my garage that I haven't used because it has problems. All the gears crunch a bit when shifting. I replaced every synchro in the trans and the result is still the same. Crunchy city.
What bothers me is that it is EVERY GEAR, I can understand if some teeth were messed up causing one gear to be a bit crunchy, but having them all crunch is driving me nuts. It has been sitting in my garage for 3 years now and I'd like to take another tackle at it.
So, what could it be?
Old 11-23-10, 11:16 PM
  #2  
Eye In The Sky

iTrader: (2)
 
cewrx7r1's Avatar
 
Join Date: Feb 2001
Location: In A Disfunctional World
Posts: 7,893
Likes: 0
Received 114 Likes on 66 Posts
You did not say is another gear box works in your car or not.
(1) The pilot bearing might be bad and is grabbing the input shaft.
(2) Alignment is bad causing the pilot bearing and input shaft to bind.
(3) The clutch pressure plate is not totally releasing the disc.
(4) The master/slave cylinders or hose is/are bad.
Old 11-23-10, 11:26 PM
  #3  
Rotary Enthusiast

Thread Starter
iTrader: (4)
 
Aeka GSR's Avatar
 
Join Date: Nov 2004
Location: Riverside, CA
Posts: 1,086
Likes: 0
Received 2 Likes on 2 Posts
I have a working different trans with the same car. Also if I "speed shift" the problem is not present.

Last edited by Aeka GSR; 11-23-10 at 11:28 PM.
Old 11-24-10, 07:28 AM
  #4  
Tequila? ..it's like beer

iTrader: (1)
 
NewbernD's Avatar
 
Join Date: Mar 2001
Location: Woodbine, MD
Posts: 1,124
Likes: 0
Received 0 Likes on 0 Posts
what gear oil is in it?
Old 11-24-10, 08:57 AM
  #5  
Senior Member

iTrader: (2)
 
blue87's Avatar
 
Join Date: Mar 2001
Location: Dearborn, MI
Posts: 255
Likes: 0
Received 1 Like on 1 Post
+1 on the gear oil.

I just put a newer jdm tranny in my car and ordered fresh redline oil. But I got the MTL by accident... Way too thin for our trans, have to shift slow so the syncros can get a grip.

Replaced with some reg 75w90 I had laying around. But it is too cold here in MI now for that, didn't think I would make it out of my driveway it crunched and ground so bad had to double clutch just to change gears since the fluid was curdled.

Drove it right back in the barn and mixed in a left over quart of the mtl with the heavy stuff and is better, once it warms up it is driveable.

I just ordered some neo synthetic 75w90 HD it is supposed to work well. But I can tell u the wrong fluid make a huge diff in the fd trans... I heard people say it before and I thought they were exaggerating... But no they weren't.

Good luck
Old 11-24-10, 02:03 PM
  #6  
Rotary Enthusiast

Thread Starter
iTrader: (4)
 
Aeka GSR's Avatar
 
Join Date: Nov 2004
Location: Riverside, CA
Posts: 1,086
Likes: 0
Received 2 Likes on 2 Posts
I tried NeoSynth and "brown label"
Old 11-24-10, 02:29 PM
  #7  
Wangan Nasty

 
Miata_mx5's Avatar
 
Join Date: Apr 2006
Location: Irvine, Southern California
Posts: 1,779
Likes: 0
Received 3 Likes on 3 Posts
Redline heavy duty shockproof oil.

Almost guaranteed to fix that issue.
Old 11-24-10, 03:18 PM
  #8  
Rotary Enthusiast

iTrader: (4)
 
Ernesto13B's Avatar
 
Join Date: Jun 2007
Location: California
Posts: 1,114
Likes: 0
Received 0 Likes on 0 Posts
+1 on gear oil. My FD crunched every single gear when I first bought it and would not shift at all into any gear at high rpm and I thought my tranny was toast. I flushed the fluid with Amsoil Severe gear 75W90 and everything now is perfect
Old 11-24-10, 04:49 PM
  #9  
Rotary Enthusiast

Thread Starter
iTrader: (4)
 
Aeka GSR's Avatar
 
Join Date: Nov 2004
Location: Riverside, CA
Posts: 1,086
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by Miata_mx5
Redline heavy duty shockproof oil.

Almost guaranteed to fix that issue.
Every high performance transmission builder I knew told me to stay away from that junk.
Old 11-24-10, 05:00 PM
  #10  
Senior Member

iTrader: (2)
 
blue87's Avatar
 
Join Date: Mar 2001
Location: Dearborn, MI
Posts: 255
Likes: 0
Received 1 Like on 1 Post
I am amazed how sensitive the fd tranny is to the fluid type... I have half a mind to try out all the popular redline/neo/amsoil/mobil one oils next summer back to back...
Old 11-24-10, 05:59 PM
  #11  
Rotary Freak

iTrader: (24)
 
AzEKnightz's Avatar
 
Join Date: Apr 2005
Location: California, SF
Posts: 2,488
Likes: 0
Received 7 Likes on 5 Posts
Originally Posted by Aeka GSR
Every high performance transmission builder I knew told me to stay away from that junk.
LOL, that redline crap is junk!

Neo didnt work? Amsoil or even dynojuice =)

-AzEKnightz
Old 11-25-10, 01:42 AM
  #12  
Rotary Enthusiast

Thread Starter
iTrader: (4)
 
Aeka GSR's Avatar
 
Join Date: Nov 2004
Location: Riverside, CA
Posts: 1,086
Likes: 0
Received 2 Likes on 2 Posts
Originally Posted by AzEKnightz
LOL, that redline crap is junk!

Neo didnt work? Amsoil or even dynojuice =)

-AzEKnightz
Hah.
Nope Neo nor dyno worked. I have Neo in my current trans and it is working fine.
I just hate having a transmission lying around that I can't fix =(
Old 11-25-10, 06:03 PM
  #13  
I luv my carbon footprint

 
mgoddard1's Avatar
 
Join Date: Mar 2002
Location: Indianapolis
Posts: 452
Likes: 0
Received 0 Likes on 0 Posts
In my experience 2 things can cause all the gears to grind:

1) Using straight gear oil instead of using special manual transmission gear oil such as NEO MTF.

2) The clutch may not be disengaging completely. Possibly a broken fork?
Old 11-25-10, 11:11 PM
  #14  
rotorhead

iTrader: (3)
 
arghx's Avatar
 
Join Date: Aug 2004
Location: cold
Posts: 16,182
Received 429 Likes on 263 Posts
For whatever reason Rx-7 transmissions are very sensitive to fluid. They love Redline, even though transmissions on other cars often don't. I have personally had Redline MT-90 solve grinding problems compared to other "decent" brands like Mobil 1.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
MILOS7
3rd Generation Specific (1993-2002)
2
10-09-15 02:19 AM
musker
New Member RX-7 Technical
1
10-01-15 05:58 PM



Quick Reply: All gears grind/crunch.



All times are GMT -5. The time now is 02:30 AM.