Mazda 2010 CX-7 shifted after fluid changed does not now

Purchased a 2010 6spd auotmatic with manual shift.

Car did not shift into 2nd gear or reverse. Felt like neutral. Let a trans cleaner do its course and did a full vaccuum flush removing all fluid.

Pan was clean. Tran fluid was black like oil.

Put 7-8 quarts of vavloline max life ATF LV.

Car shifted funny but then after a few miles it was fine. Perfect shitting like a new car in all gears in both automatic and manual.

Now it’s doing the exact same thing.

AT light comes on, high engine rev, does not always shift into 2nd or reverse. If I turn the car off and start again and put it in manual it will shift but it’s hit or miss if it shifts smooth or erratically.
Is this likely worn bands or automatic clutch? I took all the solenoids out cleaned them and put them back in.

Pan had no metal debris but it could have been cleaned up before I acquire the car.

What might be going on? Thanks

How many miles are on the car . . . ?!

The transmission service you did . . . to your knowledge, was this the first and/or only service the transmission has ever received?

90,000 miles. Car looks fairly new and it drove like a new car after fluid change.

Pretty sure it was the first change. The trans was out within the last 3 months. Had orange beed on the pan and where it connects to the engine so I imagine the previous owner was told it needs a new transmission.

When it slips going into second from first there is a high rev like it is in neutral. Something didn’t engage but if I step off the gas I can baby it back into second and then it drives just fine in second. I can usually shift with ease after I do this through all the gears until it happens again.

Each time second doesn’t engage reverse won’t either but runs fine in all other gears. Took it on a 130 mile trip yesterday and on the way home it began to slip again

You may have bought some time when you changed the fluid but it sounds like the damage was already done. The old fluid didn’t get black overnight.


Any idea what it might be? I’ve never dug inside transmissions but to me it seems like there’s some sort of leak or not enough Hydraulic pressure fluid to shift when in 2nd or reverse. Looking to get a rebuild kit and go from there

I heard it could be a band or seal.

Does the engine have to come out to work on the FS5A-EL transmission?

Did you buy this car, knowing it had transmission issues . . . ?!

I hope you negotiated a very good price . . . far lower than a similar car with a working transmission?

I didn’t pay that much, about $1400. I’m wondering if it still might be the transmission fluid.

I use Valvoline LV, but I think maybe I should have been using Type M-V for a 2010 CX-7 5 speed

I thought LV was backwards compatible but maybe its the wrong type.

The transmission was broken when you bought the car. The fact that the fluid was black like oil is an indication of that. Changing the fluid helped for a little bit but that was just a band-aid.

No the engine doesn’t but the transmission does.


Black trans fluid means the transmission is fried; or WAS fried when you bought it. It’s not the fluid type that is the problem. Now you know why the seller decided to unload it.


Glad to hear you only paid pennies on the dollar

But it sounds like you knew the transmission would need to be replaced/overhauled when you bought the car, correct?

I strongly suspect . . . as you apparently also do . . . that the seller was told the transmission was trash

Hence the low price

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No clue what might be wrong other than “it’s busted.” If you’re willing to fix it yourself, best of luck.

Hi. Yes I did definitely know the transmission was shot before I purchased. It strikes me funny that it drove fine after I did a complete flush.

When I bought the car my scanner said there was a gear ratio problem with 2nd & reverse and maybe a stuck solenoid. I reset all the codes after a flush and they’ve not returned even though I’m having the same issue once again.

After pulling the pan (which didn’t have any particulate, so I imagine it was probably cleaned since it had recently been off) and pulling all the solenoids (a code I got said one was stuck open) cleaning them and putting them back and after a long long flush, it ran and drove like a new car, shifted just fine.

Now it shifts intermittently. I’m guessing most likely something burned up and got hot and/or shot seals, since the fluid was black. But still puzzled it was shifting fine for a few miles.

I’m tempted to pull it and tinker with it myself, I mean I have maybe $1700 into it at this time and I think a decent tran overhaul kit is about $200-300. Hate to go with a pull on iffy mileage.

I like to learn, but generally I don’t do internals. Where I live (on a remote island), there isn’t a tran shop other than the fix-it-all neighbor mechanics, which is why I am thinking about doing the repair myself.

Anyway, back in the day, I believe mechanics used to drop their dirty parts in a bucket of diesel to clean them up, same with oil changes and transmission flushes. I don’t mind Berryman B12, but that stuff dissolves rubber and bones.

In short, I did a flush with diesel (as I’ve done for 20 years without incident) and filled it with new tran fluid and it ran great. Now I think there might be some residual diesel left because I can still smell it, so I’m tempted to flush it one more time before I pull the tran.

Anyway, that’s where I’m at with my project.

Thank you for all the input.