Transfer Case - 4WD Issues

A few months ago there was some snow on the ground and my 2007 CX-9 reported being in 4WD when I noticed issues getting up my driveway, it's like I lost power, even though I floored the gas the RPM's didn't increase and I just slowly climbed up the driveway. I did some searching and noticed a recall related to losing power on a hill in 4WD and went to the dealer where they did a firmware upgrade and I never had the issue again.

Now a few months later I was again pulling up the driveway in snowy conditions and started slipping on ice, the 4WD light came on and I wasn't able to pull through it. I had my wife get out and look at the wheels and noted that even though it said 4WD only the front wheels were spinning.

So I brought my car to the dealership as it is still under warranty and they told me that they couldn't reproduce as there was no snow and we weren't expecting snow; they recommended bringing it back next year during a heavy snow. I complained that it might be out of warranty then and long story short they agreed to look at it.

The next day the dealer called back and said I need a new transfer case, I asked if they found a problem and was told yes, but the mechanic was tied up and the guy at the desk couldn't tell me exactly what they found.

So now they are ordering the transfer case and it will be replaced next week. My question is has anyone else had transfer case problems? Could it be that the dealer doesn't know and is just replacing the biggest part as it is covered under warranty? Does the dealer eat some cost with warranty repairs or are they compensated well for big ticket repairs. I am just trying to gauge if there is a real problem that requires a full transfer case replacement or if the dealer is just milking an expensive warranty repair.

Sounds like they don't know. The 'transfer case' is really just a PTO added to the transaxle. The rear drive shaft is always driven, and only when needed does the REAR differential activate to accept up to 50% of the power. Also, of the car doesn't get any traction, the engine reduces power to stop the slipping. That's what that popping sound is when you spin the tires and the wiggly car light comes on.

Are you sure you don't just need better tires? AWD can't compensate for lousy traction.
Your dealer is right on the money. Several folks on this site and Edmunds have experienced the issue. You're like the fourth or fifth case of the exact same issue. Your transfer case is bad from the factory. That's why you're spinning on two wheels.

Let the dealer do their job. From what I've heard, the transfer case costs about $5,400 before labor. It's work fine afterwards. Believe me, Mazda (and no manufacturer these days) doesn't pay out that kind of warranty moolah if the issue isn't real and documentable.

Mine's functioning fine, but I wish I had the extra cash to get the extended warranty, mainly for issues like the transfer case, and the water pump that requires hoisting up the engine for the install, and any other gotcha lurking in the future.
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Don't you have to turn off the traction control? Aren't these set up to stop power from going to the wheel that is spinning and if there is no traction they're just going to stop?
Just an update, the dealer replaced the tansfer case and told me there have been other cases where they are bad right out of the factory. On my receipt it said replaced under TSB 03-005/08

I searched for this TSB, but couldn't find it, so not sure how they came up with it for my 2007 CX-9

If anyone else suspects issues with AWD/4WD I'd recommend bringing it in, I saw the dealer receipt and the repair was just over $3000
Well I hope so, I have 22K on my 2007, so will know for sure when the snow returns this fall before the warranty is up. The tech who relaced the transfer case was sure I had a faulty one and said he hadn't seen a problem with any of the replacements. I look forward to seeing how things perform with 4WD, but will have to wait...
2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
If I read my workshop manual correctly, in Mazda terminology, the unit that attach to the transaxle is called "transfer case". It transfers torque to the rear and the drive shaft is always rotating when driving. The unit that attaches to the rear differential (in front of it) is called "coupling component", which is a viscosity based multi-plate coupler. Once electronic signal is sent to it, the viscosity thicken and the plates engage one another, therefore, torque is passed thru to the rear drive shafts. The amount of torque transfer can be controlled electronically (up to 50%).

The one pointed out by sportowner is the transfer case. The one in front of the rear differential is called coupling component. In Mazda terms, that is.
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Thats why I asked. Technically, the 'transfer case' is nothing more than a PTO (Power Take Off) The actual diversion of wheel power is done at the differential.

Our CR-V was the same way, but the transfer was totally hydra-mechanical.
2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
I know. Some people mistakes the rear coupling component as the transfer case, which is actually in the front attached to the transmission. Some people call the transfer case PTO.

What I don't understand is that constantly driving the central shaft is a waste of energy. Why not bring the coupler to the front before the shaft so that the shaft rotates only when rear wheels need power?
Probably space, and engineering. Easier to fit the system in by splitting the PTO and Coupler. Imagine if that was all in one case, like a 4WD truck. Easier to adapt it to be FWD or AWD because of that design.

Also, less stress on the U Joints of the drive shaft since it's already turning.


'17 CX-3 GT
I always thought that when a transfer case goes out, or begins to go out, there were horrible grinding noises involved. Isn't it caused by bad / damaged gears inside the case?

To me, this issue sounds a lot more like the rear coupler not doing its job.
That's why I was asking. The PTO does nothing but tap into the transmission output shaft and turn the rear drive shaft all the time. The rear Coupler does all the magic according to what the control module says, so unless the PTO had a damaged or missing gear, it should have been turning. I'd think just about any problem with the AWD not engaging would be with the computer or the Coupler itself.


Mazda 6
Transfer failure

I had the issue on my 2007.

Same symptoms, poor traction in snow and no power output going to the rear wheels. The dealer diagnosed the transfer (Mazda's terminology for the PTO off the transmission). At $5400 bucks it definitely isn't just a simple PTO. Apparently, it's an active component of the Active Torque Split system that works with the rear coupler to transfer power between front and rear.

Anyway, I had the repair done a bit over a year ago and, so far, I've had no more problems.

The 4WD lamp is a failure warning indicator not an indication that the AWD system is active. If the AWD system is working correctly there should be no indicators.

Since that, the only other reason I've had to take it in is for the two recent recalls and my dealer had me in and out in about 1 hour for those.
I'd like to see an exploded view of the transfer case. It isn't very big, so I can;t imagine it containing more than gearing and possible a basic dampening system to relieve engagement stress.



Mazda 6
So would I.

Whatever is in it it's complicated enough that it has its own separate service manual. Only complete R&R and some minor external components are covered in the CX-9 Shop Manual.
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I have a 2010 CX9 GT AWD with 6800 miles on it. A few weeks ago it started making a high pitched squealing sound that sounded like brakes, every time I started it in the morning. It increased and decreased with wheel speed and quit completely after the car warmed up, about 15-20 min. First trip to the dealer, they repositioned the driveshaft. The second trip they replaced the driveshaft. They finally got it right the third trip down there and had to replace the transfer case. So it sounds like Mazda is still sending out some bad ones. I am wondering if this part is made/installed in the US or in Japan. Both the engine and transmission are done in Japan now. On my 07 CX9, only the transmission was done in Japan. Just glad to have my baby running well again. Oh .. the AWD light always flashes when I start the engine but goes off and stays off after the quick flash. My 07 did the same. Is that ok?
2017 Mazda CX-5 GT, 2016 Mazda6 iGT, 2014 Mazda3 sGT hatchback
The initial light when starting CX9 is normal. It is checking the system. The light stays on if there is an error code associated with it.
Our transmission is made by Aisin (who supplies transmission to Toyota/Lexus/Volvo/Mazda/etc.) in Japan from day one. Engines were shipped to Japan for assembly back in 2007 from Ford's factory.
Later on, Mazda modified the engine to 3.7L and revised the intake manifold. Therefore, the engines were made in Japan since then.
I don't know the source of transfer cases, but it seems to me that the rate of failure has greatly reduced for later models.

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