I'm looking for advice on my 2018 Mazda CX-5 (FWD, 129k miles) regarding a concerning 'hard clunk' I feel during gear changes at low RPMs (1,000–1,500 range), particularly in stop-and-go traffic. Additionally, during cold starts in the morning, the car violently jerks/lunges forward the very first time I apply the brakes while moving. The transmission fluid is likely original, as the dealer confirmed they did not change it during their recent service. I'm trying to determine if this is a known TCM software/logic issue (like TSB 05-006/24), a sign of worn transmission mounts, or if I should risk a drain-and-fill on original fluid at this high mileage to resolve the shift shock. Has anyone else with a high-mileage Gen 2 CX-5 dealt with this combination of symptoms, and did a software flash or fluid refresh actually fix it?
Seeking advice regarding hard clunk from transmission
- Thread starter Faheem_23
- Start date
Yes it did. The only problem was the slight bump i faced during the first start in the morning which i now suspect was due to a low fluid level.
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- 2017 CX3 AWD
Got it. So the shifting pattern reset and fluid topping off both helped.
Did you get to see the dent on the pan when it was discovered? If not, would you be willing to check it out yourself? A good look at the pan will help you decide to freak out or chill.
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Lazy2.5
2015 Mazda 6 - AT - Tuned
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- Ontario
I would get that pan replaced as soon as possible. No amount of fluid leakage is acceptable.
Agree that if the dent was deep enough to actually damage the internals, you would know, because a simply shift adapt reset would not help physical damage.
Agree that if the dent was deep enough to actually damage the internals, you would know, because a simply shift adapt reset would not help physical damage.
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- 2017 CX3 AWD
If the dent was deep enough to hit the internal components, it probably would have resulted in more than a slow leak. The pan is a very thick and solid piece of metal. The other interpretation is that a slight dent along the pan edge caused a slow leak, and that slow leak over a long period of time led to dangerously low fluid level, hence the concern over damage to internal components (like solenoids and stuff as mentioned above). Did the mechanic indicate how much fluid was added and what type? There may be clues on the invoice.
Either way, if the dent wasn't shown to me at the time, I'd want to put the front wheels on ramps, remove the belly cover, and take a good look at the pan. I'd also want to get an OBDii device and app to regularly scan for codes. I started recently to scan on each drive and found occasional codes that went away on their own or stayed away after being cleared. They didn't trigger the CEL. There are problems lurking below the surface.
If the diagnosis was from a trusted mechanic, then they would be in a better position to advise whether it is safe to continue driving until the replacement pan arrives.
Either way, if the dent wasn't shown to me at the time, I'd want to put the front wheels on ramps, remove the belly cover, and take a good look at the pan. I'd also want to get an OBDii device and app to regularly scan for codes. I started recently to scan on each drive and found occasional codes that went away on their own or stayed away after being cleared. They didn't trigger the CEL. There are problems lurking below the surface.
If the diagnosis was from a trusted mechanic, then they would be in a better position to advise whether it is safe to continue driving until the replacement pan arrives.
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Thank you everyone here for your help. I had the transmission pan replaced today and the fluid changed as well. Apparently my mechanic found that there was no filter inside the transmission pan upon opening it and the pan was bolted with a drill to prevent the leak. He told me there was definitely someone doing something fishy. I suspect it was the dealer I bought it from because when I called him, he was very rude and pretty clear that he was not going to help me with the repair. Anyways, my mechanic told me I was lucky that I bought the car when I did or else I would have had to pay for a new transmission soon. He didn't find any damage inside and the previous fluid wasn't that dirty but then he did top up 2 quarts of fluid just a week back. I hope the transmission pan is sealed well enough to prevent any further leaks. I drove the car for around a 100miles today and I can notice the difference already. The car shifts a lot smoother. Seriously, thank you to everyone here in the thread, couldn't have made it without your valuable advices.
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Solution
Lazy2.5
2015 Mazda 6 - AT - Tuned
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- Ontario
Wow! 2 quarts low is dangerous. You did the right thing by promptly taking action, first with the drain/fill, then with replacing the pan.
I would suggest doing that transmission reset one more time, so that the transmission can now learn with the filter and fluid proper.
I would suggest doing that transmission reset one more time, so that the transmission can now learn with the filter and fluid proper.
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- 2017 CX3 AWD
Glad to hear that the car is shifting fine now. Was everything else about the car checked out as well?
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