Transfer Case oil leak and lip seal change?

billzhangzy

Member
:
CX-5 Touring
Hi all
I own a 2015 CX-5 AWD (bought in the States) and currently live in Germany.
Appreciate some insight about my transfer box oil leak issue and how should I proceed, fixing something that may not be the true cause and risk to create other problems?

Since last year, I have been experiencing oil leak from my car when it's about 15,000 miles.
It's determined that the oil is from the seal (Simmerringe) of transfer case (Verteilergetriebe) on the passenger side.
However, the funny part is that the problem comes and goes, and I never knew what was the true cause of it.

Initially, the local dealer said the transfer box oil was overfilled and released the excessive (not sure if it was the dealer in Seattle overfilled it. I had my 10,000 mile maintenance in the States before leaving for Germany around Jan 2016).
Then the issue has gone for the whole summer and winter 2016, until recently I had the 20,000 miles schedule maintenance with the same local dealer.

The oil started to leak again on a road trip, and I had to stop at a garage (ATU, a reputable chain garage in Germany).
The mechanic told me the transfer box and engine oil were both overfilled and they removed the excessive (I watched they did so)

Since then, the leak stopped, but I still went back to my local dealer.
Local dealer did a check and told me that they had to replace the oil seal of the transfer case (of course they denied they had overfilled the transfer box or engine oil during the 20,000 miles scheduled maintenance)

The problem now is whether to trust the local deal to replace the seal which is costly and may not be the cause of the leak.
Does it look like the overfill has always been the cause of leak? I don't want to do such a big repair unless it's absolutely necessary.
Bottom line, I don't want to create other problems by changing the original seal while not fixing the oil leak...

Thank you in advance for your help.

Bill
 
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IMO...If transfer was overfilled the mechanic would have had to fill it up with front raised and/or vehicle was not level in anyway. Even then not sure it would cause an issue with a slight overfill. If one filled to fill line (cold) and then other dealer pulled the plug as everything was heated up.. yes some fluid from expansion would come out but this wouldn't be overfilled either.
 
IMO...If transfer was overfilled the mechanic would have had to fill it up with front raised and/or vehicle was not level in anyway. Even then not sure it would cause an issue with a slight overfill. If one filled to fill line (cold) and then other dealer pulled the plug as everything was heated up.. yes some fluid from expansion would come out but this wouldn't be overfilled either.

Thanks a lot. I've been reading some articles online as well.
From the amount of excessive oil they had to let out, it should not have been an mistaken overfill, just as you said.
However, it may lead to something more severe, I am afraid.

Maybe the transmission fluid keeps leaking into the transfer box? I have no knowledge how transmission and transfer box are actually connected in the case of CX-5, but would that be the cause? Like oil seal between they fail?
In this case, replacing the oil seal of the transfer box is not going to solve the problem right?

Just to add.
Why it happens a few hundred miles after the schedule maintenance (10,000 and 20,000)? Is it because transmission oil will be refilled during the maintenance?
I also noticed that, shifting into R from P or N will make a louder noise (than the first 10,000 miles) and noticeable shake of the car.
Are they related?

Thank you again!

Bill
 
That transfer is a completely separate unit. No way I can think of that it could leak into transmission and vice versa. It's basically a combo transfer case/front differential.

How bad was the transfer leaking? Was it leaving drops on the ground? This isn't a common item that has a leak but IIRC I thought someone reported their transfer leaking here in a thread.
 
Thanks for the explanation, Kedis
I am just so confused, if no one added additional oil to the transfer box, how come it got so full...
I also found out that engine oil was overfilled, but that's even weird if that's related.

Before the mechanic took away the excessive oil, it was dripping down quite fast from the seal, even a quick stop by the gas station, I can see 3-5 drops on the ground.
After the oil was taken, 0 drop since then.
 
I also found out that engine oil was overfilled, but that's even weird if that's related.

Who did your oil change? I checked the work for one particular Mazda dealership and the oil was high. Past the max mark. I talked to the service desk guy and asked them how much oil did they fill? He said 6 quarts. I pointed out that the manual called for 4.8 (5 quarts) for the 2.0 engine. Long story short never went back to that dealership. Also a good a idea to do you own oil changes or double check the dealer's work.
 
⋯ I pointed out that the manual called for 4.8 (5 quarts) for the 2.0 engine.
The oil capacity of your SA-G 2.0L is 4.4 US quarts! 4.8 US quarts is for 2.5L. ;)
 
The oil capacity of your SA-G 2.0L is 4.4 US quarts! 4.8 US quarts is for 2.5L. ;)

Correct 4.4. Essentially 4-point something but the dealer was putting 6 quarts in there!! Too much oil= seals that can leak.
 
Who did your oil change? I checked the work for one particular Mazda dealership and the oil was high. Past the max mark. I talked to the service desk guy and asked them how much oil did they fill? He said 6 quarts. I pointed out that the manual called for 4.8 (5 quarts) for the 2.0 engine. Long story short never went back to that dealership. Also a good a idea to do you own oil changes or double check the dealer's work.

That's a good point. Thanks!
It was done by a local Mazda dealership, and it's the biggest in that region...who would have thought? It's Germany...
 
Thanks for joining the discussion...But still it doesn't explain why the transfer box oil was also overfilled.
Do you, by any chance, know that transfer box oil refill is part of the scheduled maintenance?
There is no chance that transfer box oil was from anywhere else, right?
 
What do you bet service guy made the mistake of thinking he was working on a SkyActiv-D in Germany?

Looks like that is 5.6 quarts and every other SkyActiv motor can have .5 quart to goto fill line on dipstick.

http://oil-change.info/mazda-cx-5-engine-oil-capacity/

Only the rear diff is listed in service guide for severe use or been in water. Normally someone would have to go out of their way to request service on the transfer unit.
 
Thanks for joining the discussion...But still it doesn't explain why the transfer box oil was also overfilled.
Do you, by any chance, know that transfer box oil refill is part of the scheduled maintenance?
There is no chance that transfer box oil was from anywhere else, right?

Sorry I'm not knowledgeable enough to provide an answer here.

What do you bet service guy made the mistake of thinking he was working on a SkyActiv-D in Germany?

Looks like that is 5.6 quarts and every other SkyActiv motor can have .5 quart to goto fill line on dipstick.

http://oil-change.info/mazda-cx-5-engine-oil-capacity/

Good point, I can see this confusion occur.
 
What do you bet service guy made the mistake of thinking he was working on a SkyActiv-D in Germany?

Looks like that is 5.6 quarts and every other SkyActiv motor can have .5 quart to goto fill line on dipstick.

http://oil-change.info/mazda-cx-5-engine-oil-capacity/

Only the rear diff is listed in service guide for severe use or been in water. Normally someone would have to go out of their way to request service on the transfer unit.

Well, mine is 2.5L...they still managed to overfill my engine oil.
I am thinking moving to another dealership...just could not figure out why the transfer box is overfilled.
It's fine if it's a mistake...hope it's not from other part of the car...
 
Yeah... IMO... service person probably thought they were working on a different motor that has a different oil capacity. IIRC... isn't the the 2.5L not even available for sale in Europe? The transfer is a sealed unit though.
 
Yeah... IMO... service person probably thought they were working on a different motor that has a different oil capacity. IIRC... isn't the the 2.5L not even available for sale in Europe? The transfer is a sealed unit though.
Mazda does have higher power 189 hp SA-G 2.5L on CX-5 in Germany. It's very strange how did the German Mazda dealer "overfilled" the front transfer case. It's almost impossible to do that even if you're trying on purpose!
 
FWIW, I had a problem with a transfer case and transmission on a previous vehicle, after many months and $$ the problem ended up being a small leak in the rad was leaking into the tranny and cause all kinds of problems...as it diluted the oil. Part of it was a shoddy Chevy dealer that ended up losing their dealership when the company downsized a number of years ago.
 
Mazda does have higher power 189 hp SA-G 2.5L on CX-5 in Germany. It's very strange how did the German Mazda dealer "overfilled" the front transfer case. It's almost impossible to do that even if you're trying on purpose!
Exactly, that's why I wonder if the oil in the transfer box was actually from other part of the car, like transmission or engine oil...
 
Thanks...is it possible that CX-5 has the same design that transmission fluid can leak into transfer box? I guess some one already said no, but that's what I am mostly concerned about. Not sure if I am mistaken, the fluid is different, right?
 
No. IMO: That would not happen here. Overfill condition would have be caused by fill at some weird angle, rapidly pumping in fluid and quickly putting fill plug in or through the small breather cap on top of transfer.

AT and front diff/transfer use very different fluids as well.

On a side note I have a 20HP Suzuki outboard boat motor and this is probably typical of most outboards but you fill the lower unit oil from the bottom hole and keep pumping in until you start seeing fluid come out the top hole. Then quickly replace the bottom drain screw. Oil is thick enough only a negligible amount leaks out while you are screwing it back in.
 
Hi guys, I have an update. I later on went to another dealer in Germany.
They checked the transmission oil and re-open the valve of transfer/differential box. They found two things:
1. The oil in the transfer box again overflowed by roughly 50-100 mL (it was released a couple month ago)
2. The oil in the transfer box is same as in transmission.

Their conclusion is that, the inner seal ring (innen rechts wellendichtring) between transmission and transfer box needs to be replaced.

Do you guys know if it's a right diagnosis?
Is it the same or different oil in transfer box/differential and transmission?
If not, what's the harm of letting them mixed up in the transfer box?
I do not experience major issue with shifting when driving, and the leaking seems very slow (6 months with 100mL), is it worth the effort and money to fix?
 
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