66 Cast Plug Differential Seal

[Peter M.]

I noticed oil seepage from my cast differential plug. I am not clear from the AIM if a copper washer is called for but Paragon offers one. Assuming this is correct - what is the install order - ie Copper Washer, Red Plastic Posi Tag, Cast Plug ? I assume the Posi Tag is oversize and does not interfear with the washer contact.

[Joe L.]

Re: 66 Cast Plug Differential Seal

Peter----

I don't think that 1966 used a sealing washer for the differential filler plug. Beginning about 1965, I believe that the plug changed to an NPT tapered thread which is "self-sealing". Usually, though, seepage will be noted from these "self-sealing" threads. A little pipe joint sealing compound on the threads may be helpful at preventing this.

[Eugene B.]

Re: 66 Cast Plug Differential Seal

Peter,
Joe is correct that the copper washer was delected in '65. The '65 plug is indeed a pipe thread that has a tapper. My '65 does not have a washer.

I like his idea of pipe joint sealer to control any seepage. I don't think that you could tighten the pipe tread plug tight enough to compress the copper washer if you chose to use one. At least I would not risk tightening the plug that tight.

Hope this helps.

Regards,
Gene