I have a 2012 Mazda 5 Touring. I am having problems with the transmission. My wife was going to work and it just went haywire. So i sent the TCM and had it rebuilt. Got it back and I'm still facing problems. The AT light comes on and goes off after about 5 secs. It only comes on when driving. So trying to get a code read on it is not working. I have done as the company said that rebuilt the TCM unplug the battery and connect the two battery cables together for about 30 minutes to do a complete power dump on all systems. The fluid looks to be good no burnt smell. Showing that the fluid level is good. I checked it after i have driven it 5-10 miles. From 1st to 2nd gear the rpm go high between 4 and 5 thousand (does not happen every time). The rest of the gears shift fine. Reverse This is where the major problem is. When it does go into reverse as soon as i touch the gas it slips out of reverse. If i dont touch the gas it stays in reverse. Has anyone else had this problem. If so what was your fix.

 

Welcome to the forum

 

At this point it is not really a DIY diagnostic or to find your issue. I strongly suggest that you find (see below) In your area.
You posting suggest more problems then a TCM?

Transmission shop & Total Car Care | AAMCO

BTW the advice about the battery disconnect and touching the cables does nothing. Not sure why they would even suggest that?
Hold onto your invoice because you may not have a true rebuilt unit and only health test as most of those ECU TCM PCM companies really offer.
If you want to post the vendor here or by PM I can confirm exactly what they do.
We use several sources for our customers.

 

Thank you for your reply, but I'm going to try everything before i take it to someone. I'm retired i have nothing but time on my hands, its more of a project. Its not a daily driver so its no rush to get it fixed. I was just looking for someone who have had a similar issue and what their problem was. I should have also included that this post was a repost from like 2 years ago, that got no replies. I had put this project to the side and i was just getting back on it.

 

wow I am surprised I missed it. But like I try to keep responding to members on this forum I partisipate on up to 12 vehcle foums a day while most of the time at work. So some slip past me and I even opccationally respnd to one problem that is on the wront thread. LOL Most laugh that know me other seem to target that as a flaw in my service advise.

OK so lets get some info...
First thing that must be done!!!!
charge the battery to at least 12.50 volts and load test the battery. It must pass before we talk further. Also check the battery terminals and the leads where they attach to the starter and the ground for good clean contact.
Scan the ECU and retreive ALL the info in the panding DTC. permenant DTC and the I/M Monitors. Note them and then reset the ECU(clear)

Next I need to know:
Current miles on odometer
When was the last basic transmission service done date and miles.
How often was the basic pan fluid and filter changed? You can get a VIN history that will show at least Mazda service infom.
Have you ever gotten an ECU "flash? If so when was it and what date.

When you dropped the pan to replace the parts you thought were the issues what did the valve body look like in the way of varnish? And also what had settled in the pan and pan magnet if there was one?
I am still dubias of the TCM company you purchased your TCM can you provide the name either here or by PM so I can look into them? The mere fact that they suggested the battery disconnect to reset anything except turn of the dash caution lights has my going hmmmm about them??

 

I sent it in to upfix in good ol Buford Ga. Which i thought that i did some good research on them and had not seen anything bad about them. As they say if it does not fix your part we will give you your money back. Which they did.

 

Ok I know them..... not a bad company but... I also know how they do basic testing. I call it RED light GREEN light fail pass test. My guess your TCM got the RED light while one they senmt got a GREEN light.
@ $299 for yours it was a used tested GREEN light but not "rebuilt" in the normal sence.

Anywaywhat did they suggest after you did the battery disconnect and you recontatced them with the TCM quwestion not solving the isse?

I still need to know the other questions.

BTW there little video is flawed about the color of ATF. Many ATF are no longer tranditionally died RED. This has been misleading to those use to that color. Mazda ATF fluids for newer transmission are a dark greenish color. B&M ATF has been clear,blue and red over the decades I guess they liked all the die colors? and Amzoil or REDLINE is clear