NJ Steves Pit Viper Revival

[njsteve]

The machine shop called me today. He pulled apart the diff and found that pinion bearing race had some marks in it.

He asked if I used synthetic diff fluid and I said yes.
He then asked if the car sat a long time without driving. I said yes.
He said that was the problem.

In his decades of experience, synthetic differential fluids don't have a good fluid film thickness for long term storage like traditional fluids have. He said the races got abrasions from lack of lubrication and the rollers basically made corrosion divots in the races. He also said the synthetic diff fluids seem to attract moisture more than traditional fluids. That would explain the test results showing the presence of water in the fluid.

So he will replace all the bearings and seals and set the existing 3.54 gears back up. (which he said were fine and just need the depth adjusted a little.)

[njsteve]

Picked up the 3.54 diff today. Total cost was around $750. More than half of that was the bearing kit and seals.

Looks like Blackstone was right on the money. It was devouring the bearing rollers in the main pinion bearing, which was contaminating the fluid with iron.

That was also the "tinkling" sound I heard. The rollers in the main pinion bearing were probably around 75% of the size they should have been. And all the races were showing severe brinelling. The main pinion bearing race was bad enough that you could catch your fingernail in the divot at the 12 o'clock position in the photo.

[njsteve]

Here's the main pinion bearing. Notice how high the roller is in the first photo. And then how low it drops in the second. Now compare them to the third photo next to the low mileage pinion. You can see how worn the rollers are on the bad bearing compared to the low mileage bearing on the right.

That was the "tinkling" I could hear when I rotated the yoke and heard the roller drop to the other side of the cage slot. The damn thing is so loose it sounds like a tamborine.

[njsteve]

And the shiny, clean diff with the 3.54 gears all reset and ready to go.