Rear Differential Help

[bowvmi2001]

I purchased a 1962 TVR Grantura MKIIA about a month ago and my rear differential has a small leak at the drain plug. I want to make sure that it doesn't run low on fluids, but I am unsure where the fill plug is located. I believe that I located the fill plug at the top of the rear diff and it looks alike a 1/2 inch square nut with a hook on top. I tried to remove it, but it was stuck. I don't want to remove it with force unless I know that it is the fill plug. Also, I am unsure of what kind of rear diff it is or from which car it comes. Any help with the location of the fill plug and the type of rear diff I have would be greatly appreciated. I have uploaded two pictures, one shows the hooked nut that I believe might be the fill plug, the other photo is from another car, but is the same type of rear diff that is on my vehicle.

[Adrian@]

The filler is that hook plug...as for origin, the internals are MG banjo type, but the output shafts R and L are pretty much bespoke with 2 different versions in spline count so that reflects in planet gears (someone will correct this I'm sure) and R/L being different lengths.
Adrian@

Edited by Adrian@ on Monday 5th September 15:53

[bowvmi2001]

I was able to get the filler hole open after much fighting and swearing. I then filled the diff to what I believed to be about half full (using a crude dip stick that I made from some wire). The diff then leaked more then it ever did before I filled it, but only when driven. Which leads me to believe that I may have overfilled it with oil. I also believe that the gasket on the rear of the diff is allowing the oil to leak and I plan on replacing it. Now that brings me to my three questions.

1. How much oil should be in the diff?
2. Where can I find a new gasket for the rear of the diff and what type of material should it be made from?
3. Is replacing the gasket fairly straight forward or am I in for a surprise?

Any help would be appreciated. I am not the most mechanically inclined person, but I am learning.

[thegamekeeper]

Firstly congratulations on buying a TVR Grantura.

The "hook plug" is in fact the filler plug but the hook should in fact be a breather, dont breal it off. The capacity of the differential is 2 1/4 imperial pints, not sure what that is in American. However you should have a level plug on the RHS of the casing just below the driveshaft output flange which you remove to refill. When it starts pouring out of there its full. I find that when I fill mine to that level, the first time I get it hot and give it some beans it will expell some oil from the breather, usually onto the hot exhaust and look more serious than it is. Ignore it, it shouldn,t do it again once its found its level.
You will need to make a gasket, not difficult from either cork or heavy duty gasket paper. I would advise a VERY light smear of gasket compond either side of it to make assembly easier if doing with diff "in situ".
It shuldn,t be too difficult to replace if you can get access uner car to work but you will obviously need to drain the oil out using the drain plug.

[thegamekeeper]

I have unscrewed the plug so that you can see it. DONT damage the casing, they are incredibly rare. They can often weep from round the output oil seal so dont ignore the levels till you find out if it weeps a little. sTeVeR