Amazon/eBay Viscous Coupler (for Rear Differential)

[joe-diy]

I need to replace my Viscous Coupler on my 2015 CX-5 2.5L 6SP Auto. Has anyone used one of the Amazon or ebay aftermarket ones? They are $250-300 vs $1200+ OEM. Car has 150k on it, newer to me so not wanting to put a ton into it until I get a feel if it's a 300ker.

My question is if you were able to get the ECM programmed for the new aftermarket one. The OEM units apparently are tested and tagged with detailed results that are on a sticker that is entered at dealer when flashing. I'm sure there's an OBD2 tool I could buy as well but haven't found anything online that inspires confidence. Local dealer charges $150 IF I have the sticker codes.

I would guess the full differential + coupler kits on Amazon/eBay would be the same so if you've done one of those, what did you do for programming?

So, anyone installed one of these cheap couplers or combo kits? Care to share any details about install and or programming?

 

[N7turbo]

Torque converter?

These are precision devices, and I don't think I would trust a $300 TC.

That said, $1200 seems like a lot. But I looked at what I put in my Trans Am and it's definitely more than I paid many years ago: Yank Performance Converters SS3600LS Yank Performance SS Series Torque Converters | Summit Racing

 

[joe-diy]

Torque converter?

These are precision devices, and I don't think I would trust a $300 TC.

That said, $1200 seems like a lot. But I looked at what I put in my Trans Am and it's definitely more than I paid many years ago: Yank Performance Converters SS3600LS Yank Performance SS Series Torque Converters | Summit Racing

No, the viscous coupler. It's the "clutch" between the rear drive shaft and the rear differential on the AWD CX-X vehicles. Electronically controlled.

 

[N7turbo]

No, the viscous coupler. It's the "clutch" between the rear drive shaft and the rear differential on the AWD CX-X vehicles. Electronically controlled.

Oh, the PTU? That's what Mazda calls it. No idea, sorry.

(the torque converter is a viscous coupler, by the way)

 

[sm1ke]

Found this video doing a quick Google search. Looks like it can be done at home, but I don't know how much the tool costs.

Depending on the cost of the tool/software, and the amount of time it might take to get everything up and running, it may be easier to just have the dealer do the reprogramming. Especially because you'll probably never need to do this again during your ownership.

 

[joe-diy]

FIXED UPDATE!

I made the repair this weekend and thought I would share my overall learnings.

1. Multiple shops refused to troubleshoot the issue, pointing to an old TSB from Mazda related to the Rear Differential and some ball bearing. They recommended I take to the dealer which I found frustrating from independent shops. The car has 150K on it, the TSB was not a recall so would have cost money just to get diagnosed. The shops also charged me to tell me about a TSB...they are off my short list for now.

2. The issues I was seeing were as follows:

a. "Wobbly" feel when making tight turns. As the car heated up from driving, this changed to a vibration and after a lot of driving, full "popping", shuddering and what I would describe as binding. It's really important to note that when cold, it was hard to detect anything but when hot, it felt like the rear end was done for.

b. As vehicle warmed up, I would feel a clunk or knock when hitting accelerator or letting off gas at higher speeds (going straight), particularly on the highway.

c. Disconnecting the electrical connector into the Viscous Coupler immediately eliminated symptoms. Reconnecting it made them return. To me, this demonstrated that the differential gears were not what was binding since they would still be turning but the Coupler would be disengaged from the transfer case. This does disable AWD and turns on the 4WD dash light, just so you are aware. This step was recommended by someone on Reddit.

All of the issues either didn't start until, or got much worse when the vehicle was driven for 30+minutes.

The replacement was straightforward but I would still call it at least an intermediate job. Car was raised on 4 jack stands and I laid on my back to disconnect drive shaft 4 nuts (it slides back off of 4 bolts), disconnect wire harness from multiple attachments and from connected cable and remove 4 bolts connecting Coupler to Differential. I had to hit drive shaft with hammer to separate and also hit the coupler with a hammer to separate. Some diff oil did drain out from there but I suspected that was from the separation since most of the inside was dry. There was also blood red thick oil that I suspect was leaking from the actual coupler. I had read the internal fluid can break down and is what causes the issues I was having.

I did put a bead of Peramtex transfer case gasket maker around Coupler but not sure I needed to.

Everything went back together and the vehicle drives great. My son took it 250 miles back to college and reports all is good. Since it was aftermarket, there were no codes to program and I suspect that will lead to a shorter lifespan for the replacement. Whether this was a good choice depends on how long it lasts. OEM was $1000+, Amazon was $250.

Here is the actual part I used from Amazon for reference:

https://www.amazon.com (commissions earned)

And here is the OEM Part (You can find for a little cheaper)

https://www.mazdapartsfactor.com/oem-parts/mazda-2013-2018-mazda-viscous-coupler-key02797xa?srsltid=AfmBOoqylHvVcdXpuZ8HaL6T4f9gFYtYQzb2pQmmUMwUAcUHSAwf3rgx

I'm happy to answer any questions but hope that this helps a future traveler. These Couplers were used for at least 5 years, maybe more so you may want to check it out if someone is telling you to spend $4000+ on a new rear differential.

 

[HyFlyer]

Thanks for taking the time to write up a report of your experience!

 

[yrwei52]

FIXED UPDATE!

I made the repair this weekend and thought I would share my overall learnings.

1. Multiple shops refused to troubleshoot the issue, pointing to an old TSB from Mazda related to the Rear Differential and some ball bearing. They recommended I take to the dealer which I found frustrating from independent shops. The car has 150K on it, the TSB was not a recall so would have cost money just to get diagnosed. The shops also charged me to tell me about a TSB...they are off my short list for now.

2. The issues I was seeing were as follows:

a. "Wobbly" feel when making tight turns. As the car heated up from driving, this changed to a vibration and after a lot of driving, full "popping", shuddering and what I would describe as binding. It's really important to note that when cold, it was hard to detect anything but when hot, it felt like the rear end was done for.

b. As vehicle warmed up, I would feel a clunk or knock when hitting accelerator or letting off gas at higher speeds (going straight), particularly on the highway.

c. Disconnecting the electrical connector into the Viscous Coupler immediately eliminated symptoms. Reconnecting it made them return. To me, this demonstrated that the differential gears were not what was binding since they would still be turning but the Coupler would be disengaged from the transfer case. This does disable AWD and turns on the 4WD dash light, just so you are aware. This step was recommended by someone on Reddit.

All of the issues either didn't start until, or got much worse when the vehicle was driven for 30+minutes.

The replacement was straightforward but I would still call it at least an intermediate job. Car was raised on 4 jack stands and I laid on my back to disconnect drive shaft 4 nuts (it slides back off of 4 bolts), disconnect wire harness from multiple attachments and from connected cable and remove 4 bolts connecting Coupler to Differential. I had to hit drive shaft with hammer to separate and also hit the coupler with a hammer to separate. Some diff oil did drain out from there but I suspected that was from the separation since most of the inside was dry. There was also blood red thick oil that I suspect was leaking from the actual coupler. I had read the internal fluid can break down and is what causes the issues I was having.

I did put a bead of Peramtex transfer case gasket maker around Coupler but not sure I needed to.

Everything went back together and the vehicle drives great. My son took it 250 miles back to college and reports all is good. Since it was aftermarket, there were no codes to program and I suspect that will lead to a shorter lifespan for the replacement. Whether this was a good choice depends on how long it lasts. OEM was $1000+, Amazon was $250.

Here is the actual part I used from Amazon for reference:

https://www.amazon.com (commissions earned)

And here is the OEM Part (You can find for a little cheaper)

https://www.mazdapartsfactor.com/oem-parts/mazda-2013-2018-mazda-viscous-coupler-key02797xa?srsltid=AfmBOoqylHvVcdXpuZ8HaL6T4f9gFYtYQzb2pQmmUMwUAcUHSAwf3rgx

I'm happy to answer any questions but hope that this helps a future traveler. These Couplers were used for at least 5 years, maybe more so you may want to check it out if someone is telling you to spend $4000+ on a new rear differential.

Thanks for the write up. I believe the reason why you don't need to reprogram the rear differential is because you replaced only the viscous coupler, not the entire rear differential. A formal Moderator Chris_Top_Her here replaced the entire rear differential on his 2014 CX-5 with a used one and did require the reprogramming the 4WD Control Module with characteristic value from the replacement rear differential.

Also, consider putting a revised vent hose from a TSB which could prevent the water intrusion into the rear differential and ruin the rear differential.

CX-5 Rear Diff and Transfer Case Fluid Change: Tools, Parts and Links