A rotted rear diff housing on a 2018 GM product.

[JTK]

This is a different one. A 2018 Buick Encore that came in with the assumption it needed rear axle seals due to gear oil leaking from the rear. Wound up being corrosive materials trapped in the aluminum webbing on top of the rear diff, corroding it to the point the housing cracked! This is the follow up video on it.

 

[atikovi]

Being on top of the diff that would have been a perfect candidate for epoxy or urethane patch.

 

[LenZee]

Looks like someone didn't fluid film their undercarriage.

 

[AZjeff]

Salt.

 

[JTK]

It's another spot I'll have to blow out and goop up with woolwax on my 2021 Traverse and 2021 Equinox. GM mounts the control modules for the rear coupler/clutch right on the rear diff housing, which is super handy because those rot right off too. That's why this Buick was in, in the first place. The control module was corroded causing no AWD and other electrical issues.

 

[I<3oil]

Gg GM

 

[JoelB]

Man that's a lot of rot for a 2018. It seems New York vehicles rust faster than here. I'm guessing due to higher average temps in winter.

 

[LenZee]

Man that's a lot of rot for a 2018. It seems New York vehicles rust faster than here. I'm guessing due to higher average temps in winter.

Its the enormous amount of salt they dump. And they probably never wash it.

 

[atikovi]

Its the enormous amount of salt they dump. And they probably never wash it.

That should be outlawed since there are alternatives.

 

[SC Maintenance]

I thought when aluminum corroded the film created on top protected the rest of it from further corrosion?

How does it corrode all the way through a heavy housing - in a few years no less? Did they use some sort of fastener that caused Galvanic Corrosion?

 

[andrew_j]

Looks like someone didn't fluid film their undercarriage.

GM did not design it appropriately for conditions.

 

[PF52]

Eric O. needs to check his spelling.

 

[JTK]

Eric O. needs to check his spelling.

I didn't notice that. LOL

In regards to the corrosion he sees, I think a lot of his customer base are dirt road drivers. The salt combines with the dirt trapped in these cars and just makes matters worst. It seems like the aluminum alloys they use these days don't stand up to corrosion well at all, especially when bolted to steel components.

 

[LenZee]

GM did not design it appropriately for conditions.

My wife has family in that area and they have lived there since the 60's. They hardly ever wash their cars and same thing happens to GM/Ford/Toyota/Nissan/Mazda. I don't think they ever had a car make it to 100k without severe rust problems. If they properly washed the undercarriage it would have made a huge difference. Plus a lot of local roads are gravel which scratches the h@ll out of the under body.

 

[andrew_j]

My wife has family in that area and they have lived there since the 60's. They hardly ever wash their cars and same thing happens to GM/Ford/Toyota/Nissan/Mazda. I don't think they ever had a car make it to 100k without severe rust problems. If they properly washed the undercarriage it would have made a huge difference. Plus a lot of local roads are gravel which scratches the h@ll out of the under body.

The undercarriage automatic washes are using a mixture of salt water reclaimed from drain/settled blended with fresh water.

We don’t wash the undercarriages here and cars last about 15-20 years unless some body work was done as they never can fix it properly so it does not rust .

 

[Danno]

Just curious if undercarriage / body panel treatments are allowed in NY State?

We use annual treatments such as Krown, and the rust issue basically goes away.

 

[LenZee]

The undercarriage automatic washes are using a mixture of salt water reclaimed from drain/settled blended with fresh water.

We don’t wash the undercarriages here and cars last about 15-20 years unless some body work was done as they never can fix it properly so it does not rust .

You must have less salt and less gravel roads. Not all car washes use reclaimed water. In NJ they used a lot less salt compared to NY.
Now I'm in Missouri and they use even less salt than NJ but don't plow properly and still see rotted out newer cars (mostly pickup beds). I used to fluid film my cars and wash often, Now I go to Omaha to have it done professionally.

 

[JTK]

Just curious if undercarriage / body panel treatments are allowed in NY State?

We use annual treatments such as Krown, and the rust issue basically goes away.

There's plenty around. Krown shops starting showing up in my area 6-7yrs ago. There's others that have been around forever as well.

 

[JoelB]

Its the enormous amount of salt they dump. And they probably never wash it.

Our roads are literally white for months during the winter, that's not unique in the salt belt. Environment plays a role here for sure.

 

[Trav]

It is a Daewoo made to last a few years with parts from Korean coke cans . Daewoo are not Hyundai, they are the bottom of the barrel trash. Even the metal cradle is looking pretty sad, I figure that car is a few years beyond its sell by date.

I thought when aluminum corroded the film created on top protected the rest of it from further corrosion?

How does it corrode all the way through a heavy housing - in a few years no less? Did they use some sort of fastener that caused Galvanic Corrosion?

Aluminum is a self preserving metal but once other elements are added to create an alloy that quality can be diminished. Some aluminum alloys are much more corrosion resistant than others.