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Blown transmission question

The dealer told my brother that his transmission was beyond repair because he added too much engine oil during a routine oil change that he did himself the car only has 9k miles (toyota corolla 2008) I could not find anything to support this from looking online and was wondering if the dealer is just pulling his chain to make a profit or is this really something that can happen?

Some info might help in formulating a wild guess.
Automatic or manual transmission?
What exactly were the symptoms?
Towed in to the dealer or what?
How far overfull?
Engine hydrolock?

Sorry I am not so knowledgable about cars
it is an automatic
at the time of total death he drove it about 8 blocks after bringing it home from the dealer(about 4 miles from dealet to home) to fix a sluggishness it was having they said they fixed that(500 dollars) then it just jerked a little and died. He got it towed to the dealer.
Not really sure about how far overfull he said he put in about 4 quarts of oil after each oil change that he did himself.

not sure what is engine hydrolock but it did die he was able to restart it but it would not move so he got it towed.

Thanks for your comments ok4450

I am a little confused. Was the oil added to the engine or the transmission?

Adding too much oil to an engine can certainly damage the engine. I could see a link that could cause damage to the transmission, but somehow I don’t think that is likely, but I am uncertain on that part.

Adding engine oil to a transmission certainly is not a good idea either and I would not be surprised with damage due to that to the transmission.

I’ve got a bunch of questions. In your follow-up post, obvilously he had the dealer looking at something. And they charged him $500.00 for a fix? On a new car he hasn’t even owned for a year? What was the original reason for taking it to the dealer, and what was that diagnosis? And why charge him $500.00 for what should have been a warranty fix? This car is too new for it’s first maintenance service.

The engine and transmission do not share oil, so how does changing engine oil affect the transmission? And if the engine oil was over filled, typically this would have no affect on the transmission at all. HOWEVER, we’ve had previous posts about people accidentally draining the transmission, then adding more oil on top of the oil already in the car, and having transmission problems due to lack of transmission fluid. Does this sound plausible? If so, your brother is on the hook for this, because it is damage due to negligence.

I agree with BustedKnuckles that there is just too much in the original post and in the follow-up that makes little or no sense.

*Why is someone paying a dealership any money at all (no less $500.00!) for diagnostic work or repair work on a 2008 car that is covered by multiple warranties?

*Was the excess motor oil added to the engine or to the transmission?

*Why is someone who apparently does not know how to change oil correctly doing his own oil changes on a brand-new car?

If the car’s owner grossly overfilled his crankcase with oil, any resulting damage is not covered by the car’s warranty–nor should it be covered.

If the car’s owner put motor oil in the transmission, any resulting damage is not covered by the car’s warranty–nor should it be covered.

If the OP has described things accurately (and I tend to think that what we are being told is NOT accurate), I think that the OP’s brother should not blame anyone other than himself.

If the events were described accurately, the car’s owner is apparently unaware of the existence of warranty coverage on his car, and has allowed himself to be cheated into paying for work that should not cost him one dime. However, since it is not easy to make sense of the muddled information provided, I do want to offer one possible interpretation that could have resulted in the dealer handing the car owner a very large bill. If the dealership found–let us say–that the crankcase was overfilled and the transmission was dry–then of course, warranty coverage on the engine and transmission would have been immediately voided. And, then depending on whatever “cures” the dealership attempted, it is possible that the car owner could have been given a valid repair bill.

It is nice to want to save money by doing one’s own car maintenance, but if that person does not know what he is doing, then it is very much the same as shooting yourself in the foot. Self-confidence is nice, but knowledge trumps self-confidence in most instances, and this would be one of those instances.

Regarding the oil change–and anything else that the car owner did underneath the car–if the car’s owner had purchased a decent repair manual, that would have illustrated the relative locations of the oil drain plug and the transmission drain plug, and it would have stated the capacity of the engine crankcase. Someone with experience might not need this information, but clearly the person who decided to do this DIY maintenance DID need some technical information before plunging into a procedure that he did not know how to do correctly.

I really believe that the OP has either been given incorrect information or is transmitting information to us incorrectly. However, if everything happened exactly as stated, then I think that the old saying, “A fool and his money are soon parted”, would be applicable here.

Do you guys sometimes get the feeling bored 14 year olds sit around and amuse themselves by posting stuff like this?

We definately need a lot more information on this one. Engine oil wont hurt the transmission. I have run automatics on 100% engine oil before while doing my experiments and have never had any catastrophic failures, and I beat on them and try to blow them up. His original post and even his follow up post makes no sense at all.


There needs to be far more detail provided and I don’t follow it even after the second post.

The scenario I was considering, and it’s a bit far-fetched, would be if the engine hydrolocked at speed due to excessive oil, the wheels kept on rolling, and some transmission internal gave up.
Splines on an input shaft, inside the differential gears, etc?

I’ve got into a few Subaru automatic transaxles in which the final drive oil had either leaked out, or as more commonly happened, someone drained it by mistake thinking it was the engine oil plug.
The owner would then motor on down the road oblivous most of the time to the gear whine until there was a catastropic bang.

The engine was still revving, the halfshafts still turning, and the differential would shed teeth when the pinion seized up along with splitting the transaxle case open.

well my brother is definantly no rocket scientist but he has been changing oil on his cars for many years and knows the difeerence from transmission fluid and where it goes from oil and where it goes and how to change the oil and filter. I was wondering if anyone ever heard of such nonsense as adding too much oil to the engine that would cause the transmission to blow out as that is what the dealer is telling him has happened. I am not sure what the 500 bucks were for and if it was anything to do with the transmission then we have 2 issues one is that the dealer swindled him out of 500 bucks but more importantly what ever they may have done to the transmission may have caused this issue so they could swindle him out of 2k-3k more. Thanks for helping out with all your suggestions now I have a ton to ask him and see if we can get to the bottom of this mess tomorrow.

Thanks again