differential question for the experts

[Ed Riefstahl]

Greetings,

Now that I have the rear axle refurbished and ready to reinstall in my car, something is still puzzling me.

Last fall when I split the two halves of the differential I immediately saw the male splined end of flex joint had snapped completely off the yoke. What has puzzled me is the fact that the bolt through the center of the spline that attaches the flex joint to the ring gear assembly was laying in the spline completely loose.

I don't recall anyone else mentioning this as being a failure problem, but I'm certainly wondering if it was. I've driven this car 65,000 miles since purchase in 2001 with no issue with the differential. Now all of a sudden one day it just snapped.

I've driven the car a little hard at times, but never abused the car or even laid rubber with it. I use the low gear occasionally to pull out into traffic, but am careful not to chirp the tires as it shifts into 2nd. With 4.08 gears, it's a lot of torque in 1st gear for sure.

Any idea what would have caused the bolt to come loose. Is it possible that it was never put in or tightened? I did put locktite on the bolt when I installed the new joint. I suppose it's possible the bolt could have spun loose at the time the spline broke, as the ring gear would still be turning but not the axle.

I guess some things just bug me and this is one of them.

Kind regards,

Ed Riefstahl
Erie, PA
1966 230SL (Ms Magoo)
1970 280S (Miss Daisy)
1989 300SE (Majestic)
1999 BMW Z3 5 speed
1991 BMW 318I 5 Speed
1997 Toyota Paseo Convertible - Red 5 speed (have you ever seen one?)
1997 Ford Ranger Step Side 54K
2023 Mazda CX 5

[ja17]

I have seen the same type of failure on several others in the past. I try to use a new lock washer, a little locktite, and torque to specs to make sure the bolt stays tight!

[Ed Riefstahl]

"I have seen the same type of failure on several others in the past. I try to use a new lock washer, a little locktite, and torque to specs to make sure the bolt stays tight!"

Hi Joe,
I did all of the things you suggested above, so I guess I'm on the right track and that's all we can do.

A later axle had it's appeal for several reasons, one is apparently the later cars have a larger diameter spline in the flex joint. In the end I opted to just stay with the original axle and drum brakes.

Thanks for suggestions,
Ed