MG Car Repair: 73 Midget Differential Problem?, differential unit, ujoint

Question
Hello.

I have a question regarding my 73 Midget.  Today it did something I was not expecting (and haven't heard of before, but I'm pretty new to Midgets).  The vehicle runs great, and shifts great.

Here's the issue.  The driveshaft moves, but the car does not.  I (very safely and with assistance and the car chocked) had my brother put the vehicle in first gear so I could find out why it wasn't moving.  I looked under the car (without getting under it in any way) and there was a slight grinding noise coming from the rear end and the shaft spun but no movement.

I'm thinking I need to replace the entire differential unit.  Does that sound right, or is it maybe the Ujoint?

Thank you for your expert knowledge.

DavidK

Answer
Hi David,
You need to put the car on a lift or on jack stands and get under it and look at the differential flange and hand turn the driver shaft and with the brake off note if hand turning the driveshaft will slightly move one wheel. If it does try to move one wheel it may not be a bad differential but may be a twisted off axle on one side.

The only way to know for sure is to remove both axles and remove the third member and examine it as it could just be the spider gears too.

Howard