TR4/4A Wrench?

[Winston]

I'm changing out the differential fluid, and would like to review. Reviewed the Haynes. Turning to the Super Haynes manual, (all you folks).
Best wrench is probably Whitworth, that not being able to utilize, the best alternative. I've got top notch Craftsman they'll be primary. Is there a square socket at the parts store?
1 1/2 pints of Hypoid High performance gear oil.(80-90 wt.)
Hope the old body can contort and torque at the same time, mine not the car's.
Thought's?

 

[Geo Hahn]

Not Whitworth. As I recall a 7/16" 8-point socket does the usual original plugs (both drain and fill). There is also a purpose-made square opening wrench (Joe Alexander, Moss, probably others) which works well and has a opening on the opposite end for the handbrake adjustment.

Undo the fill plug first so, should you run into a problem getting it loose, you can still drive the car.

Edit: This wrench: https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=49346

 

[TR3driver]

7/16" 8-point socket. Preferably 1/2" drive. Got mine at Sears.

Unless your plug is already badly mangled, that will grip just as well as the purpose-made square wrenches available from the usual suspects.

With milder damage, you may need to either drive the socket onto the plug, or rig a prybar somehow to hold it in place. The plug is an ordinary pipe plug, so replace it if there is any damage. I prefer hex socket plugs with magnets (MMC), but the square head ones are easier to find at the hardware store.