J-spec trans install
08-09-05, 02:15 AM
#1
J-spec trans install
During my last NASA event at Joliet, I blew up my 3rd and 4th gear syncros. Not sure why, there was no direct incident that I can recal that would have caused it.
I decided to get a low mile j-spec transmission from Brian, based on info that John Magnuson posted a while back in this thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/great-source-inexpensive-low-mileage-used-fd-transmissions-393397/
Brian is in Los Angeles and sells them for around $550, that is a great deal, and you get the j-spec shorter 5th as a bonus!!! :-)
his email is: ss427bb@hotmail.com
In 5th I read 80 at 3K, but keep in mind my speedo is surely off since im on 18 rims. My tire/rim overall diameter is larger than stock.
although i have a workshop manual for the car and know the car well, there was great info on when i searched the forum, so i wont duplicate it, but here are a few notes from what I did:
- some say you have to drop the ppf.... you dont, i did not. it will hang on the diff and rotate downward, its fine there until you get the new trans in.
- drain the trans first, otherwise you may dump fluid everywhere when you pull the propellarshaft out.
- you actually can get to all the trans-to-engine bolts from under the car and can tighten them better from under there. You need like 4 long extentions on the socket.
- watch the harness on the trans, it has like 3 or 4 connections and they can easily get smashed or pinched during removal/install.
- MAKE SURE MAKE SURE MAKE SURE that the clutch piston is seated on teh fork properly BEFORE pressing the clutch. Use the trans inspection plates to look in there, you can see it with just the bottom inspection plate open. If you dont have it seated and push the clutch in it will push the piston out and dump brake fluid all inside your bellhousing. Then you have to take the clutch slave cylinder (or whatever the hell its called, im not a mechanic!!!) out to to re-install the piston and clean the mess.
- also, be sure to rememebr to push the clutch fork forward to snap on the retaining ring 'thingy' that is on the pressure plate part of the cluth. Once it pops in it will hold the fork in place properly.
I decided to get a low mile j-spec transmission from Brian, based on info that John Magnuson posted a while back in this thread:
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/great-source-inexpensive-low-mileage-used-fd-transmissions-393397/
Brian is in Los Angeles and sells them for around $550, that is a great deal, and you get the j-spec shorter 5th as a bonus!!! :-)
his email is: ss427bb@hotmail.com
In 5th I read 80 at 3K, but keep in mind my speedo is surely off since im on 18 rims. My tire/rim overall diameter is larger than stock.
although i have a workshop manual for the car and know the car well, there was great info on when i searched the forum, so i wont duplicate it, but here are a few notes from what I did:
- some say you have to drop the ppf.... you dont, i did not. it will hang on the diff and rotate downward, its fine there until you get the new trans in.
- drain the trans first, otherwise you may dump fluid everywhere when you pull the propellarshaft out.
- you actually can get to all the trans-to-engine bolts from under the car and can tighten them better from under there. You need like 4 long extentions on the socket.
- watch the harness on the trans, it has like 3 or 4 connections and they can easily get smashed or pinched during removal/install.
- MAKE SURE MAKE SURE MAKE SURE that the clutch piston is seated on teh fork properly BEFORE pressing the clutch. Use the trans inspection plates to look in there, you can see it with just the bottom inspection plate open. If you dont have it seated and push the clutch in it will push the piston out and dump brake fluid all inside your bellhousing. Then you have to take the clutch slave cylinder (or whatever the hell its called, im not a mechanic!!!) out to to re-install the piston and clean the mess.
- also, be sure to rememebr to push the clutch fork forward to snap on the retaining ring 'thingy' that is on the pressure plate part of the cluth. Once it pops in it will hold the fork in place properly.
Last edited by damian; 08-09-05 at 02:21 AM.
08-09-05, 10:31 AM
#4
Originally Posted by damian
- MAKE SURE MAKE SURE MAKE SURE that the clutch piston is seated on teh fork properly BEFORE pressing the clutch. Use the trans inspection plates to look in there, you can see it with just the bottom inspection plate open. If you dont have it seated and push the clutch in it will push the piston out and dump brake fluid all inside your bellhousing. Then you have to take the clutch slave cylinder (or whatever the hell its called, im not a mechanic!!!) out to to re-install the piston and clean the mess.
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10-18-05, 03:57 PM
#8
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not to be a know it all, but if I'm correct, the shorter 5 gear only comes with the trannies out of the 99 and up jspec FD's, this is due to the increase in wheel size and rear end gear from 4:10:1 to 4:30:1, plus the added 120lbs from the 99 and up models. (Later models are heavier)What year car is your tranny from? MY 92 and 94 jspec rations are the same, but different from my 2001rs Rx7. Just my imput though. Hope I didn't step on anyone toes.
10-18-05, 05:34 PM
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I need one of these trannies bad... My 5th gear syncro has gone to hell and rev is no better. I will be sure to pick up a jdm trannie when I have some extra cash. Thanks for the write up 
10-18-05, 11:19 PM
#14
Rotary Enthusiast
Damian:
Glad you like the tranny. I found Brian very easy to work with and I hope you did to. Of course I was able to pick mine up and I guess you had to get it shipped. Also, if you're only turning 3000 RPM at 80mph you must have really tall wheels. Go back to stock size and be faster!
Indian:
I don't know if the 99 and later have a different 5th gear ration. But I know that even the first year FDs had a shorter 5th gear in Japan.
T-von:
Of course of the J spec trannies have syncros. They're indentical in every way except they don't have the US spec economy granny 5th gear ratio.
US Spec 5th gear ratio: 0.719:1
J Spec 5th gear ratio: 0.806:1
So you will get a about a 12% increase in your RPMs in 5th gear using the J Spec transmission. I like the lower 5th gear ratio a lot better for two reasons:
1) It accelerates a lot better at freeway speeds in 5th... no more need to downshift to 4th for a decent punch
2) You can reach your top speed much faster (in fact I think top speed is increased because you're in a meatier part of the powerband at high speed) and the car will actually accelerate much better after you shift into 5th. Of course only a few racetracks require 5th gear.
Downside? I maybe lost a tiny bit of fuel mileage when I cruise on the freeway.
-John
Glad you like the tranny. I found Brian very easy to work with and I hope you did to. Of course I was able to pick mine up and I guess you had to get it shipped. Also, if you're only turning 3000 RPM at 80mph you must have really tall wheels. Go back to stock size and be faster!
Indian:
I don't know if the 99 and later have a different 5th gear ration. But I know that even the first year FDs had a shorter 5th gear in Japan.
T-von:
Of course of the J spec trannies have syncros. They're indentical in every way except they don't have the US spec economy granny 5th gear ratio.
US Spec 5th gear ratio: 0.719:1
J Spec 5th gear ratio: 0.806:1
So you will get a about a 12% increase in your RPMs in 5th gear using the J Spec transmission. I like the lower 5th gear ratio a lot better for two reasons:
1) It accelerates a lot better at freeway speeds in 5th... no more need to downshift to 4th for a decent punch
2) You can reach your top speed much faster (in fact I think top speed is increased because you're in a meatier part of the powerband at high speed) and the car will actually accelerate much better after you shift into 5th. Of course only a few racetracks require 5th gear.
Downside? I maybe lost a tiny bit of fuel mileage when I cruise on the freeway.
-John
Last edited by John Magnuson; 10-18-05 at 11:22 PM.
10-22-05, 06:44 PM
#16
Thanks for the nice write up guys.. I am glad you are happy with the Jspec Gear Boxes.. Anyway, too anyone who may need one, I have plenty.. at least 25 left..Price still the same. $550.00 plus shipping.. I do have 1 or 2 later year models 1997-1998 that are really clean, LOOK BRAND NEW..VEry low miles under 16,000 miles. I am asking $850.00 plus shipping for the later type and i have 2 of them...
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Japan2la@yahoo.com
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