I'm just trying to find casting numbers on my TH400 and 12 bolt rear end, I've searched all over and can't find anything except on the rear end: 0140 and in another place 9969, and a GM8, but nothing that looks like a casting number. I've searched about 100 websites trying to find out where they should be, I think the tranny should be on the left just above the rear plate??? Any ideas. Also do I just compare the teeth on the rear end to get the gearing ratio??

Thanks,
Sean.