Kit Trasmission??
 

Hello,my trasmision sounds to changes 3º.. synchro??

There is kits to reconstruct?
Sells who them?

You can buy rebuild kits including synchros, however the synchros are only made by Mazda. I don't know if the rebuild kit shops in the US sell to Spain. So at least you can get all parts from Mazda.

Take care that if your problem is grinding 3rd gear, the synchro is only one part of several that make a good 3rd gear shift. If you replace the 3rd synchro usually it does not completely solve the problem.

David

What is the best solution?

Grinding when changing express.

Honestly, the cheapest solution is a good used transmission. The challenge is to find a good transmission and I'm not certain you have these available in Spain. Here in the US it is easy because there are importers who move these parts from Japan. Maybe one of these importers can ship instead to Spain, I'm not sure.

If you must rebuild, buy a new 3rd gear, synchro, and clutch sleeve. Use a synthetic GL-4 gear oil in 75w-90. Then replace all bearings and seals.

Since spare parts are not as easy in Spain, you could try the 75w-90 GL-4 gear oil. It probably will not solve the problem but at least it is easy to try.

http://cgi.ebay.com/ebaymotors/ws/eB...m=350166800892

This 800$ cost to me.
The problem is that it does not have failures.....

Considering your location, you would be better off finding someone in Japan to purchase a used transmission from. Try contacting the fellas at RHDJapan and ask them if they can source a used transmission:

https://www.rhdjapan.com/

Hmm, it depends, I'm in the same predicament but my case is cracked. If you have a local junkyard you can scavenge the place for a transmission or get a cheap syncro ring set from drivetrain.com. That is the same predicament I am in with my case. I'd say look for a transmission with a nice case and go to drive train for new parts. all the parts needed are 342.88 in total ( I did the math and I have rebuilt a couple myself) depends on the transmission you use but a 2 1/5 nut remover is needed to get the entire assembly off the mounting plates that hold the rods that the gears sit on. With careful documentation and multiple baggies labeled with colored stickers you can rebuild your tranny your self. There are no archives on entire tear downs but if you have yours out take a couple of pictures of it. 2nd through 4th are always the synchros to go so order them from Drivetrain because the factory synchros are 244 dollars for a set of 4 and leave the 5 to you. You may as well get the set and cryo treat them as well as wpc them too. There is a cryo plant in Great Britain that does it for 60 bucks American to get the entire transmission cryoed so a couple of synchros is cheap. The tools needed to do the build are: brass drifts, needle punch, bearing puller, gear puller, aluminum pipes, vernier caliper, machinist rule, 90 rule and a digital micrometer that comes in handy. A Haynes or Mazda factory manual can give you all the torque specifications for your transmission. Also, drivetrain.com offers manuals with step by step rebuild instructions for you. The original manufacturer of the transmissions for RX-7's was Borg Warner which was installed in 4 wd Jeeps from the same time. A 4 WD setup may be possible if you find a Jeep in your local junk yard.