Burned Transmission Fluid 2018 CX-5 AWD

Hoping a Mazda Tech may be able to provide technical info as to what kind of transmission damage is likely by severely burned tranny fluid. Trans has been acting "different" since shortly after purchase. (See History paragraph below). Mazda dealership has my 2018 CX-5 AWD with shifting problem. Threw a P0847 code (Transmission Fluid Pressure Sensor/Switch B Circuit Low). Technician ordered sensor to replace but when trans was opened, trans fluid was severely burned. Tech recommended replacing entire trans as fluid was so bad. Dealer service dept took photos and sent to Mazda to see what they thought. Mazda said replace sensor and put it back together. So now complex tranny has a new sensor, but has possible internal damage due to severely burned fluid. Looking for technical terminology to share with Mazda HQ explaining what else may have been damaged inside tranny.

History: 6/21/19 I purchased Certified used 2018 CX-5 AWD with 4,168 miles on it. Vehicle was a dealership loaner car. After driving it for several days, noticed the driveabity was not similar to previous 2017 I test drove. Noticed slightly nervous shifting, occasional searching for gears, and what I thought was slightly hard shifting. Looked at forums etc. 7/25/19 with 8128 miles took the vehicle in to have Rocker Arm Recall #3719F performed and described driveability issue. Checked out fine with no tranny or shifting problems. Still didn't seem like a nearly new-car smooth tranny. Back to dealer 8/22/19 with 9396 miles for first oil change, inquired if they had other tranny complaints told them still didn't seem right. Said they didn't see any issues. Back 11/15/19 with 15040 miles for second oil change, again mentioned shifting slightly erratically, inspection showed no issues. 12/22/19, just over 16,000 miles, check engine light came on 5 miles from home. Threw a P0847 code (Transmission Fluid Pressure Sensor/Switch B Circuit Low). Researched online which said damage could occur if driven, had the car towed to dealership 12/23/19. Car is still there 1/8/20. Requesting photos and and dealership correspondence for my records.
 
Last edited:
V
2014 Mazda3 S GT auto, 2008 MX5 6-speed
Did they not at least replace the fluid? I believe that it is highly unlikely that no wear/damage occurred. It'd be good if you could find out the function of the switch. Is it simply an alarm that is output when fluid pressure is low or high? If so, the fluid should not be burnt/overheated unless the switch was not outputting a signal that illuminated the warning light. In that scenario, low pressure for an extended amount of driving time could cause damage, I would think.
 

Ronzuki

South Central PA
L
2018 CX5 Touring
V
w/ Pref Pkg
Mazda said replace sensor and put it back together. So now complex tranny has a new sensor, but has possible internal damage due to severely burned fluid. Looking for technical terminology to share with Mazda HQ explaining what else may have been damaged inside tranny.
Many things, and they know it. What's the root cause of flakey behavior and now burnt fluid, at that kind of mileage, is the real question. Nothing good. The tech knows the tranny is done and replacing is the right thing to do, but, who's gonna pay then? So much for the "Certified Pre-Owned" gimmic aye? One simply pays more for that moniker. All it has to do is keep rolling long enough to outlast whatever initial warranty period you were given with the purchase and then it's no longer their problem. Legally it maybe, or may not be, but you'll need to step up to the plate (attorneys). Who ya think is going to prevail?

Did you happen to purchase an extended warranty of any kind with this CPO purchase?
 
V
2017 CX5 AWD Touring
That's ANOTHER REASON why I hate when vehicles don't include transmission dipsticks. A simple 1 minute check of the fluid level and condition via dipstick tube would have spotted the problem.
 

Chris_Top_Her

Banned
Moderator
Contributor
L
San Antonio, Texas
V
'15 CX-5 Miata AWD
Lemon, call the BBB in the warranty book before it's out of warranty and you become SOL
 
V
2018 CX-5 Sport
To me, there is a fault in the transmission that caused it to over heat and burn the fluid. Changing the fluid is a band aid, the same will probably happen. I would try to get a new transmission under warranty. The other possibility is that the transmission fluid was so low that it didn't keep the parts cool and lubricated. Again, with the crappy performance that you talked about, I would try to get a new free transmission.
 
V
2018 CX-5 Sport
It is a pita that they did not put an easy access transmission dipstick. It would have cost what, 15 bucks to add it.
 
Many things, and they know it. What's the root cause of flakey behavior and now burnt fluid, at that kind of mileage, is the real question. Nothing good. The tech knows the tranny is done and replacing is the right thing to do, but, who's gonna pay then? So much for the "Certified Pre-Owned" gimmic aye? One simply pays more for that moniker. All it has to do is keep rolling long enough to outlast whatever initial warranty period you were given with the purchase and then it's no longer their problem. Legally it maybe, or may not be, but you'll need to step up to the plate (attorneys). Who ya think is going to prevail?

Did you happen to purchase an extended warranty of any kind with this CPO purchase?
"Certified Used" warranty receives an extension to factory warranty...Bumper-to-Bumper supported through 1/11/23 or 48,000 miles. Powertrain valid through 1/11/2026 or 100,000 miles. Spent months researching small SUVs and intentionally stayed away from CVT transmissions due to potential early failure...and wound up with a potentially early failure if this isn't replaced. Went through similar fight 30 years ago with FOMOCO. Bought a "new" 89 Bronco II that had bodywork repair. Took six months of repainting attempts to fix and meet Florida Lemon Law requirements. Finally took an attorney to send a letter to Ford. Two weeks later I was picking out my new Bronco II. Don't want to go through that again, but will if I have to. Simply want an undamaged transmission. And yes Lbear... a dipstick would be nice. I'm the guy who actually uses it regularly. Owned over 40 vehicles and maintained them properly. Will go through the chain of command starting with Service Manager, Dealership Owner, Regional Manager, then Mazda North America...but it sounds like Mazda North America is already involved and calling the shots. May just start there. Thanks for the input.
 
Did they not at least replace the fluid? I believe that it is highly unlikely that no wear/damage occurred. It'd be good if you could find out the function of the switch. Is it simply an alarm that is output when fluid pressure is low or high? If so, the fluid should not be burnt/overheated unless the switch was not outputting a signal that illuminated the warning light. In that scenario, low pressure for an extended amount of driving time could cause damage, I would think.
They opened the tranny so they will replace the sensor and fluid at a minimum. Will do some research as to the function of the switch to see if it's primarily an alarm...but due to the "nervous tranny" for months, seems something mechanical has been going on well before the check engine light came on. I live in the Smoky Mountains so hills affect transmission performance; after checking forums about hard shifts being related to normal, but stiff torque converter lock-ups, and the assurance from the dealership service dept. all was well, just figured it was the new normal. At least I know it wasn't my imagination. Thanks for the input.
 
To me, there is a fault in the transmission that caused it to over heat and burn the fluid. Changing the fluid is a band aid, the same will probably happen. I would try to get a new transmission under warranty. The other possibility is that the transmission fluid was so low that it didn't keep the parts cool and lubricated. Again, with the crappy performance that you talked about, I would try to get a new free transmission.
Agreed, band-aid fix with potential trans issues in the future. Hoping they do the right thing...It's a warranty issue.
 

Avoidin Deer

Central Virginia
Contributor
V
2019 CX-5 Reserve
I guess the upside is that the dealer is not the dishonest link in this chain. That's one less hurdle to cross (and an ally) when you escalate to Mazda Customer Service.

Perhaps a visit to a lawyer might be a good idea...not to go Scorched Earth on them as your first option, but to advise you through each step of the process. The value of this repair is certainly worth a hundred bucks to sit down and have a conversation. And if you eventually need to take action, they you have laid the groundwork properly.
 
V
2013 Mazda CX-5 Sport FWD Auto
If I could do it over again I would have gotten a lawyer from the start for an issue I had with my Focus. Had a lemon law case with Ford that I handled on my own right until I lost the BS BBB manufacturer sponsored arbitration. Work with Mazda corporate first as they are the issue. If Mazda corporate won’t agree to a transmission replacement at the service centers request, a nasty gram from a lawyer would be money well spent.
 

ColoradoDriver

Gen-1 Kodo Design
Contributor
V
2014 CX-5 Touring AWD
That's ANOTHER REASON why I hate when vehicles don't include transmission dipsticks. A simple 1 minute check of the fluid level and condition via dipstick tube would have spotted the problem.
You maybe aren't referring to the CX-5 with this comment, but in case you are, the CX-5 DOES have a transmission fluid dipstick. Problem is, it's under the airbox and you have to check it at a very specific temperature while running. Definitely not an easy dipstick like checking the oil for sure, but it is there.
 
  • Like
Reactions: JT2
V
2014 mazda cx-5 touring FWD
This is scary on a car this new and low miles.If the fluid was burned I wonder what kind of debris was in the transmission pan.To burn fluid requires slippage which generates heat and debris.Slippage possibly caused by low main line pressure (pressure which forces the friction plates together).Computer detects slippage by comparing input and output shaft speeds and commands max line pressure which causes slam (hard shifts)shifts.Caused by pressure control valve defective/intermittent from sticking due to debris.I'd be concerned about how much life is left in the clutch packs and if the system was cleaned to eliminate any debris floating around.
This reminds me of what I experienced with a GM 4T65E trans that was in my Buick Regal,The PCS valve(pressure control solenoid) was known to be defective and would "stick" and not control line pressure properly.It was intermittent and would result in loud whining sound similar to gear whine (noise due to transmission pump pressure maxed out),hard shifts ,hot trans temperature and a shaking feel on takeoff (it's called "launch shudder").It could be remedied alot of times by just shutting the engine off for a few minutes and restarting .Then it worked fine until the next episode.Mine rarely happened in winter .Mostly occurred in hot weather.I'd stay on top of this before it gets out of warranty.
 

Ronzuki

South Central PA
L
2018 CX5 Touring
V
w/ Pref Pkg
the CX-5 DOES have a transmission fluid dipstick. Problem is, it's under the airbox and you have to check it at a very specific temperature while running. Definitely not an easy dipstick like checking the oil for sure, but it is there.
Might as well be called 'sealed for life' with where that 'stick' is located and how it is accessed for a simple look see at the fluid's health. CVT or conventional, makes no difference, they're designing everything to live long enough to get the vehicle beyond standard warranty. Anything beyond that is a bonus. Evidenced by they ridiculous changing of the burnt fluid and the sensor which basically indicates the trans is cooked and should be replaced.

Jatco JF011E CVTs in our Suzuki SX4 and Kizashi...absolutely nothing in the owner's manuals' service schedules regarding changing the fluid...ever. Nothing in the FSMs either. Well many years later and failures are piling up, mostly in the Kizashis as they're heavier and have more power. Years after that comes a service bulletin stating, umm yeah maybe, you should change the fluid at normal service intervals. Right...too late for many. Those CVTs do have a very usable dipstick just like the oil which had always been the puzzling part of the situation. Waiting too long to change the fluid (turns out no different than conventional every 30k miles or so) and the CVT will only last to 150k if your lucky. Changed mine out at 80k it was black. During the third consecutive drain and fill I could at least see daylight through it while it was draining. Car was performng more as it did when new afterwards.

Manufacturers are cheapening the very basic and fundamental parts of every car that makes it go down the road in order to shift the dollars for adding the 'stuff' everyone thinks they need, and which is seemingly ever so much more important (until this kind of BS occurs), in order to keep sell prices in the realm of...sell-able. 'Stuff' that has zero to do with making the machine go down road reliably and w/o fault. Robbing Peter to pay Paul. Why is this such a difficult concept for the masses to understand then when the manufacturers readily deny deny deny and fight against replacing major components? You're not going to beat them in court if it comes to that. The odd man may, but at what ultimate cost? The best course of action for the OP is to be overly polite and pleasant when contacting corporate hoping all the while that whom ever you're speaking with is in a good mood. Speak to a lawyer if you like, what's another $150 when you're looking at many thousands to put the car back to right.

Me, I'd let them change the fluid again because it definitely needs it, and then one more time...because it'll need it. Let them swap out the 'your trans is fried' sensor, and dump the thing ASAP. Cut your losses. I dumped a perfectly good low tech 2014 Wrangler for the 2018 CX5 because for over a year the dealer along with factory tech support tech couldn't keep water from entering the cabin from the hardtop's A-piller windshield intersections, running down and behind the dash, dripping from wiring, speakers, OBDII connector and ultimately flooding both floor pans. Fiat corporate cut me off after I don't know how many botched attempts at stopping the leak, only to make it worse and inject other issues. Fiat Corporate threw down the gauntlet and said they were done and weren't going any further with it. Challenge! We both knew I wasn't going to 'win' anything at that point
 
Last edited:

ColoradoDriver

Gen-1 Kodo Design
Contributor
V
2014 CX-5 Touring AWD
Might as well be called 'sealed for life' with where that 'stick' is located and how it is accessed for a simple look see at the fluid's health.
Sure, for the average user out there. I really don't understand manufacturers making it hard to read fluid levels. Like, why can't you use a normal dipstick?
 

madar

Contributor
V
2016.5 CX 5 Touring AWD, 2015 SCION XB
Definitely sounds like the trans should have been replaced. I guess we're getting a look at how Mazda is backing their CPO warranty- they aren't.
 

Ronzuki

South Central PA
L
2018 CX5 Touring
V
w/ Pref Pkg
I really don't understand manufacturers making it hard to read fluid levels. Like, why can't you use a normal dipstick?
I can't stress this enough... all of the extra non-sense in a car today you think you want, need, and can't live w/o..."distracted driver assist technology" and "infotainment" crap, well, the dollars to pay for all of that have to come from somewhere. While a dipstick and stand-tube are not mission critical, unfortunately, critical components also are, and have been, cheapened. It is really that simple. GM caused themselves some serious grief (dead people and lawsuits) over cheapening a component within their ignition switches to save $0.02 per switch. As I recall, an engineer testified (lied) under oath to the gov on national TV he had no knowledge of the change. Well, months later an ECN (Engineering Change Notice) contained within an email was produced w/ his signature indicating he in fact approved it...whoopsie. Can you say jail-time? Do the math over the number of vehicles sold. That's merely one component in a machine w/ thousands. Besides that, you don't check/service your fluid and burn up the trans, manufacturers sell more parts and more vehicles. That's why they're in business, to make money, which quite simply, is the goal. All of this "creating and experience" smoke and mirrors marketing fluff manufacturers spew (like kodo) is just that. Once again, the designed life span target window is the warranty period for practically anything and everything today. Realize it, understand it, and come to grips with it.

So my advice to consumers is this, be careful what you wish for. What's more important to the OP now? All of the extra costly garbage in the rolling techno-marvel, or, the fact that his expensive new transportation device will very soon no longer be carrying out its primary function...rolling down the road transporting him to and fro?
 
Last edited:
V
2017 CX5 AWD Touring
You maybe aren't referring to the CX-5 with this comment, but in case you are, the CX-5 DOES have a transmission fluid dipstick. Problem is, it's under the airbox and you have to check it at a very specific temperature while running. Definitely not an easy dipstick like checking the oil for sure, but it is there.
I meant the access is so ridiculous and impossible to check, that it as well not even have one. As far as the fluid being "lifelong" that is another BS marketing and EPA play. No fluid lasts forever. That is impossible. Ask any fluid dynamics engineer. They will laugh at you when you tell them Mazda and other manufacturers claim the trans fluid is "forever".
 

Latest threads

Latest resources

Top