So I had a pretty bad transmission leak recently in my 89' D100 (318) , it was leaking from the pan gasket, front and rear seals. I've had no trouble finding the gasket and the front seal but I've been to every parts store in my area and gotten the same response...they don't have it and they can't order it. The seals they have that were cross mapping to the part number on the seal from my truck were all much to big. I'm having the same problem with all the ones I'm finding online as well. I was curious if anyone on here had the same problem? Where did you find the seal or what did you send up doing for a replacement? Thanks in advance. The Transmission in the truck is the A999 instead of the 727

 

This it?

 

I found that one last night and it looks like it, but the part numbers listed didn't match the number on the seal so I was hesitant to order it. I can always send it back I suppose if it doesn't fit

 

Different manufacturers will have different numbers on the seal. Check the measurements. That's what counts.