5th gear synchro replacement
#1
5th gear synchro replacement
While I had my drivetrain out for a rebuild, I decided to be proactive and do the 5th gear synchro upgrade because I did get an occasional grind before tear down. I'm using the following as a guide:
THIS IS NOT MY WRITE UP. I simply saved this for other people so DON'T contact me about the tools
When tearing down I notice from a quick visual (I don't have the bearing off yet to be sure) that the synchro looks to be identical to the new one I received from Ray. It's bronze in color like the new part. The synchro on the write up that is broken is not bronze. I do not see anything broken in my synchro and I'm now wondering if I already have the upgrade? I am the second owner of this car.
Would someone be able to affirm my suspicions? Perhaps the grind was just because I had worn engine mounts as it only happened a few times under WOT pulls.
Adam
THIS IS NOT MY WRITE UP. I simply saved this for other people so DON'T contact me about the tools
When tearing down I notice from a quick visual (I don't have the bearing off yet to be sure) that the synchro looks to be identical to the new one I received from Ray. It's bronze in color like the new part. The synchro on the write up that is broken is not bronze. I do not see anything broken in my synchro and I'm now wondering if I already have the upgrade? I am the second owner of this car.
Would someone be able to affirm my suspicions? Perhaps the grind was just because I had worn engine mounts as it only happened a few times under WOT pulls.
Adam
#2
Moderator
iTrader: (3)
Join Date: Mar 2001
Location: https://www2.mazda.com/en/100th/
Posts: 30,780
Received 2,564 Likes
on
1,824 Posts
we used to do a lot of 5th gear synchros, they are easily broken. also the color of the old one depends on the oil its been soaking in, and how long its been in there. if you notice, the inside of the trans in the pics you link isn't sparkly clean.
when you get the old one out, try to pull it apart, its more common for them to be cracked than to be broken in 3 pieces
when you get the old one out, try to pull it apart, its more common for them to be cracked than to be broken in 3 pieces
#6
RX-7 Bad Ass
iTrader: (55)
It's really not too bad to do a synchro, I've done a few of them.
Making the puller is the hardest part, and that's not too hard. Get a regular gear puller and some long L-shaped steel stock to make extensions. I got the steel at Lowe's, no big whoop. First puller I made used flat steel, but it bent with the force applied to it. The L-shaped steel (or even box steel) is a much better choice.
There is also a spring that bolts to the tail housing that was updated with the 5th gear revision. This spring makes it harder to mis-shift into 5th gear, which is the root of the problem with the broken synchros. The new synchro can be broken again by shifting into 5th at 2nd gear redline, and that revised spring will all but eliminate that.
I've driven cars with and without the updated spring, and without it is quite easy to miss the shift into 3rd gear.
Dale
Making the puller is the hardest part, and that's not too hard. Get a regular gear puller and some long L-shaped steel stock to make extensions. I got the steel at Lowe's, no big whoop. First puller I made used flat steel, but it bent with the force applied to it. The L-shaped steel (or even box steel) is a much better choice.
There is also a spring that bolts to the tail housing that was updated with the 5th gear revision. This spring makes it harder to mis-shift into 5th gear, which is the root of the problem with the broken synchros. The new synchro can be broken again by shifting into 5th at 2nd gear redline, and that revised spring will all but eliminate that.
I've driven cars with and without the updated spring, and without it is quite easy to miss the shift into 3rd gear.
Dale
#7
Thanks Dale. I will agree, so far the hardest part is building the puller. I actually have enjoyed the tear down. I did buy the new spring as well. I also have a garfinkel torque brace and plan to instal a trans brace. The only mis shifts going forward should be from driver error
The link in my first post made it very easy to tear down.
Adam
The link in my first post made it very easy to tear down.
Adam
Trending Topics
#8
Well, I finally got the bearing off and down to the synchro. Sure enough it was the upgraded synchro already. However, it isn't perfect. There are ridges on the flat backside. I also noticed the bearing is a little worn and noisy. I'll go ahead and replace her.
It's hard to see the ridges in the photo, but they are there.
It's hard to see the ridges in the photo, but they are there.
#12
These are the only improvements I know of, but I'm far from an expert. Ray Crowe will have both if you call. Just ask for the upgraded 5th gear synchro and shift select spindle. I discovered my bearing is bad and will end up buying another tomorrow.
Here are photos of the new spindle and where the old one is. It's located on the back of the trans and you can replace it without dropping the trans.
Adam
Here are photos of the new spindle and where the old one is. It's located on the back of the trans and you can replace it without dropping the trans.
Adam
#17
OK, so I'm pretty sad that I made a mistake and didn't catch it till the trans was back in the car. The shift select wasn't properly aligned with the rods when I put the extension housing back on. Any tips on how I get that aligned and on?
I have got the extension housing off (with the trans in the car!) and am trying to test fit and make sure I get it down before reapplying sealant. It's in neutral both the selector and the trans, but I don't see how I rotate it to align the finger with the rods.
I have got the extension housing off (with the trans in the car!) and am trying to test fit and make sure I get it down before reapplying sealant. It's in neutral both the selector and the trans, but I don't see how I rotate it to align the finger with the rods.
Thread
Thread Starter
Forum
Replies
Last Post
rgordon1979
3rd Generation Specific (1993-2002)
40
03-15-22 12:04 PM
[For Sale] Scratch & Dent, Used, and Open-Box Sale!
SakeBomb Garage
Vendor Classifieds
5
08-09-18 05:54 PM