My other truck is a 92. Sweet reliable truck but each time I order a new drain plug from Genos they send me an 18 mm thread size. Then when I go to change the oil the new drain plug is too large to fit in the pan.

Does anyone know where I can get the correct size? If so, what size is it?

I must say that Genos is the best in trying to help as they sent the second plug free. Oh well if anyone needs a new drain plug I have three of them extra that fit my 2002 second gen not the 1st gen.

I went down to the local parts store and got a drain plug for my 2000. Might try that. Dorman was the brand iirc.

I'm headed there today for other things. I did not think they would have a Cummins part, but will bring the 18mm plug to compare.

Thanks much Kitt.

You say your plug is smaller then 18MM?  18MM is the smallest cummins oil drain plug size that I know of.  Could you have been sent a 22MM?

Yes, the parts store (O'reilly) has all sizes, plugs and seals. I bought a package of seals from 12mm to 20mm, with nylon seals, and some kind of fiber seal. It's grey colored, and the parts guy recommended that over the nylon one. (they tend to snap if over tightened.