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2006 Mazda 3 Shifting Problems

9K views 13 replies 8 participants last post by  Thrash 
#1 ·
I have a 2006 Mazda 3 2.3. Shifting into every gear works fine, except 3rd. Most of the time when I try to shift into 3rd, it will either just straight up grind and not go into gear at all, or go into gear and then get pushed back out. If I hold the shifter hard enough, it will make a loud bang, but stay in gear. Any ideas what could cause this to happen? The clutch isn't over a year old, and it hasn't been driven hard since it's replacement. Linkage maybe?
 
#2 ·
I just posted about the same thing yesterday, I have an 07. There a number of things that could cause it, but there are a few that are the usual suspects. I just replaced my Rear Motor Mount with a CP-E 75 durometer, it's magical. It stiffens the whole car up and makes the gearbox much more fluid. It did help quite a bit, but I'm still not out of the woods. However, I've been running Royal Purple 75w90 GL-5 gear oil and it was suggested to me to use Redline Mt-90 GL-4 because of our transmission's synchros. The GL-5 doesn't play nice with them.

More times than not, people will tell you it's the motor mount and for the most part it helps a great deal. I'll let you know if I have any luck with the new gear oil.
 
#3 ·
Thanks for the info. My motor and clutch were replaced a while ago, so I don't know what gear oil is in it. I'll defiantly take a look at the rear motor mount too.
Again, thank you.
 
#4 ·
I went to two different shops and saw two different mechanics. They both came up with the same answer, that its the synchros, and they're very, very bad. Looks like I'll be driving around without 3rd for a while.
 
#5 ·
So I just swapped out the GL-5 75w90 Royal Purple gear oil for GL-4 MT 75w90, no more 3rd gear grinding! I'm dumbfounded. I went for a quick 5 minute drive and continually shifted from 2nd to 3rd and no issues. I drive just short of 60 miles to and from work (120 round trip), so I'll give you a better review/update tomorrow after a longer driving stint. Initial results are promising! You may want to grab some. I bought some (3 - 1 Quart)on Amazon for $44, you may want to give it a try before spending more on new synchros.
 
#13 ·
Had the same issue when I switched to RP
It was insta-grind
Had to replace my 3rd gear syncro and switched to RedLine at the same time
 
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