well today i was driving my s4 TII and i was beatin on it and when i went to shift into 5th it made a grinding sound and it blew out 5th gear...i have every gear but 5th and its making a bad grinding sound when i drive it...my question is....is there anyway to just replace 5th gear easily or do i have to rebuild the whole tranny?has anyone had this happen to them? am i better off trying to find a used tranny or should i rebuild the one i have?

 

Can you get into 5th gear?

 

Have you tried shifting into neutral and revving the engine up a little bit, then trying to go into 5th... You probably killed a syncro...

 

Technically the gears are always meshed. The noise you're probably hearing is the "dog teeth". The dog teeth are linked to the output shaft and lock in to the gear of your choice.

The synchros are wear items that are inside the dog teeth that spin up the gears / intermediate shaft to match the output shaft speed, to make the interface go smoother.

http://auto.howstuffworks.com/transmission.htm

If you actually did some real damage, it's easier and cheaper to buy a used tranny then try to repair one. If you go to AAMCO they'll try to charge you 2 grand or more to do it. Find a used turbo 2 tranny with low milage and find a garage to bolt it up for you. Consider installing a new pilot bearing while you're at it.

With that said, I've got a spare NA tranny in the back which I think I'll disassemble and try to rebuild... for fun.

 

it goes into 5th but it dosent do anything its like theres no gear there....and when im driving it makes a terrible grinding sound in ever gear like theres stuff flyin around in there but like i said it does drive in every other gear...is that just a syncro or is it compleatly shot

 

where is the best place to find a used tranny in the pa,nj and md area?

 

you might pull the drain plug and see what chunks fall out.

 

lol i pulled the tranny out tonite and the drain plug had alot of metal on it then i took the bottom inspection pan off and there was what looked to be a couple whole gear teeth but i saw nothing wrong with any of the gears in that section...where is 5th gear located in there?

 

5th gear is in the back section so you can't see it by removing the inspection cover, you probably stripped the teeth that holds the gear to the output shaft.

i will be doing a writeup on overhauling the manual TII gearboxes in the next few days to give an idea of common failures.

 

Get A Miatabox!!!

 

a pos miata tranny is not going to hold 300, 400 or 500+ RWHP

the TII tranny is a good box but after 180k or more miles they just get tired. a couple hundred bucks in parts and a full day of time to get a damn near new tranny again would be worth it if you ask me.

 

Please please please keep going with your writeup. I've got a spare NA tranny I was going to try rebuilding.

 

unfortunately this is only for TII trannies.

i haven't pulled apart an n/a tranny to see the differences yet but by the looks of the differences between the cases they are not going to be all too similar. the FD and FC trannies are almost identical minus the extension housing/shifter assembly differences though.

it may give you an idea of what to expect but it will likely be a whole different can of worms in dealing with. special bearing pullers need to be fabricated or ordered from mazda to do the procedure. just give me a few days, i finished up an FD tranny last weekend and am working on an FC TII tranny right now.

 

Going in a tranny.... never been there... seems to scary... Have you seen the pics of them in the FSM... too many parts.... Might try it one day if I have an extra one just laying around...

 

The diagram always makes it look worse than it is. Also it's my old junk transmission, so if I doesn't go back together, oh well. The only thing that concerns me is the need for special tools.

I had a look at the Haynes manual comparing the NA and Turbo trannys and they look similar, but different.

 

it can be very sketchy doing them which is why almost no one will touch one, just like auto trannies most people who will only touch them is people who specialize in doing just them and nothing else. i try to focus my expertise in every area of the car not limiting myself to one general area but the gearboxes auto/manual can be intimidating but the key is organization and documentation of the disassembly process and maybe even labelling parts or making a diagram of your own as you go so you know how it is reassembled if you lose track. i have a picture memory so this helps a lot in reassembling but things go in order and sometimes that is where you need a guide.

 

there's a tranny shop in da bronx.perez transmissions felix is the owner and he is very fair and honest .i'm positive he will rebuild your tranny for less than a grand.hit me up if you need more info.

 

well i took the tranny up to dave at kdr and he took it apart and 5th gear was compleatly striped....every gear was chewd off..and he tried to get it apart but aparently when it blew out it bent the countershaft and he couldnt even get the one gear off it...so it was cheaper to just buy a used tranny...he said it would cost like 600 in parts...he said he never saw 5th gear blow out befroe............has anyone here heard of that happening?

 

The first time I took off my UIM (yes, UIM, I was a noob) I labeled almost everything. When I put it back on, the only thing that didn't work out for me was the throttle cable clip brace thingy (2 bolts, holds the rubber ring in the middle of the throttle cable). I lost it for a while and couldn't figure out how the hell it hooked up.

So....

+1 for labeling.