19 September 2014

The Saga Continues

So in our last installment I mentioned the transmission whine. A look on the forums suggested that, given the symptoms, the problem was most likely the center drive bearings.

Center drive is AWD speak for transfer case. The center drive is basically a limited slip differential with a viscous coupler that is driven on one side by the transmission and on the other side it drives the rear wheels. Under normal operations everything turns at the same speed, but in corners it allows the wheels to turn different speeds.

Like when you are pulling into a parking spot, for instance.

Fortunately you can dig into the center drive without pulling the transmission, it's about a two to three hour process to do so but it's not difficult. So I broke out the took set and pulled the tailshaft cover off of the transmission to check the bearings and sure enough I found two of them to be bad.

But wait, there's more.

Not only were two of the bearings bad, the center differential has come apart as well...which means it has gone bad, too, which is why I was getting the clunk in the front end during the tight turns. With the center diff locked up as it was the car is basically a 4WD instead of AWD, which is why on dry pavement the front tires would slip and cause the clunking noise.

Not struts.
Not driveshafts.
Not wheel bearings.
Oh no, that would be too easy and cheap.

Yeah...that's a $500+ part...but fortunately I found it for $411 shipped.

Looks like it will go back together next week then.

I did dodge one bullet, though, in that I didn't drive the truck too long after the clunking had stopped (the clunking stopped when the center differential viscous clutch came apart. At that point the center differential was no longer locked up and the rear wheels were no longer being driven at full power). It seems that generally when the snap ring comes off the center diff (which is what happened) it usually gets sucked into the gears. Because I didn't drive the truck very far in that condition, the gears were spared.

If they hadn't been, this might be a shorter story.

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