[maz3way]

Hi There,

It's an automatic transmission.

(If there's a better place to post this in the forum, please let me know.)

My first indication was the dashboard light came on "AT" (with skid marks) and after that the transmission would not shift into 3rd or higher gear. For sometime it's been kinda kicking when put into reverse.

Then one day when I put it into reverse it slammed into gear!

I'm assuming I have a serious transmission issue.

Questions:

How much does the car computer ECU? control the shifting and/or operation of the transmission?

What's the best transmission shop to go to ie. AMOCO etc? I'm not to excited to take it to a Mazda dealer.

Would it make sense /be worth swapping out this transmission for another used one or better to have this one rebuilt?

Is there a place I can find an owner's manual for this car online?

Any other troubleshooting I can do my self? I'm going to check the transmission fluid level.

I live in Naples, Florida, I would be interested in a referral to a good transmission shop / mechanic in this area.

Or is there a regional forum that I can locate a good shop / mechanic in this area

Thank-you in advance for your speedy response to this post as I'm in a time crunch to get this car checked out.

 

[theblooms]

It's not uncommon for the Transmission Control Module to go bad, mostly because of the idiotic placement Mazda has for it: directly on top of a scalding hot transmission! When this started popping up, I actually moved the TCM in my wife's MZ5 to the firewall.

Anyway, there are services that can rebuild your TCM for a mere fraction of what it would cost for a new one. I can't remember who it is, but if you look on the Facebook Mazda3 forums, there's a guy with a good reputation there that does them for about $300 give or take.

This actually is a job you can do yourself with simple hand tools, but know your car will be down in the time that you have the TCM out for repair.

You have to remove the battery and battery box, and once the battery box is out, the TCM is right there. (And by the way, this is a perfect time to change the transmission mount! You've already done 90% of the work!)

 

[Grendel65]

Welcome to the forum.

 

[maz3way]

Hi theblooms, Are you saying all my woes could be caused by the TCM? And it the facebook forum called ~Mazda 3 Owners Club~ Thanks for your reply.

 

[theblooms]

Hi theblooms, Are you saying all my woes could be caused by the TCM? And it the facebook forum called ~Mazda 3 Owners Club~ Thanks for your reply.

I'm not there, I don't know, I'm just saying that's one possibility. And yeah, the Mazda 3 Owners Club. You may also want to join the Mazda5 club too, because the cars are very, very similar, and therefore have similar issues, the TCM being one of them.

About the only issues our cars have are the are the TCM, the motor mounts (which absolutely will fail), and the rear upper shock mounts tend to break. Really though, that's pretty much it. And all of those things are very easy to repair/replace.

Here's a video of how to replace the transmission mount. The process is exactly the same to get to the TCM, as they're right next to each other. In fact, you can clearly see it next to the mount, it's the little silver box with fins on it. I moved mine up to the firewall. I took some fuel line, split it with a razor knife, then wrapped it around the brake lines that run down. I then used heavy duty zipties and mounted the TCM over there, away from the hot transmission.

 

[Grendel65]

I suggest getting your ECU/TCM scanned using a professional shop grade Diagnostic scanner connected directly to your OBDII Diagnostic connector and get the codes first before guessing anything.

The re-location is a good idea , you can also thermal wrap the TCM.

 

[maz3way]

I appreciate your input Grendel65.

 

[Grubbworm]

I have had a similar problem with my wife's 2005 Mazda 6 going into "Limp Home Mode". See my post here: (2) 2005 Mazda 6 Drivability Issues - Resolved. | Mazda 6 Forums (mazda6club.com) I am not sure if this will help, but worth a try.

 

[maz3way]

Thanks for your reply Grubbworm. I read the above post and wow you went through a lot to resolve that issue!
I have a couple questions. Is the “AT” light and the Traction Control light one light or two? The light that comes up on my dash shows "AT and 2 skid marks. What does that light mean?

Also, is there a PDF or digital version of a 2010 Mazda 3 owner's manual that would show all the dash lights and what they mean? Or do I need to purchase a hard copy on ebay etc.?

 

[Grubbworm]

Two separate lights.