detailing transmission mating seam

I need some tips on getting the mating seam on a transmission to look good. I usually just fill what I can with filler and file or sand smooth. But, I end up with a smooth line down the middle of a rough (for cast iron in this case) finish. That don't look all to swuft. I want to incorporate a little more detail on this one.

PS, my appologies, my manners have escaped me this evening. This being my first post, I spect I should introduce myself. My name is Matthew and I've piddling with models for a while off and on. Started when I broke my leg back in '95, snow skiing of all things. "Come on Matt, go with us. Nothin's gonna happen to ya. The ski's pop right off when you fall". Yeah, sure, don't you believe it. Anyway, Got a ZR-1 kit. Been spending money ever since. Gotten a little older and moved up to real cars now. Got a '66 C10 pickup to take a crack at. We'll see how it turns out. Outstanding site far as I can tell. The how to section has been most helpful. Afraid I won't be much help as of yet, but if the occasion does happen to arrive, I'll do my best to respond directly. Don't be strangers. Got an AOL IM name, email, and what have you. Haven't figured out the web page deal, but I might dabble in one of those one day. I love to talk and meet folks I can relate too. Too bad there's only 24hrs in a day. And yes, my people really do call me Cornbread. Well, about half of 'em do. The other half calls me Bigin, except for my parents. Ever since I can remember, they've called me dammit. "Dammit, get in the house, Dammit, turn off the water, Dammit, get your brother out a that hole." I just started answering to it :iceslolan . Everyone seems to be good people. Thanks

Sand and smooth the seam as usual, and restore the texture. You'll need Tamiya basic putty and Mr. Thinner or compatible products.
Thin the putty with thinner, and dab it on the transmission case with a brush, q-tip or whatever you think is useful. After putty is applied, you can touch it with rough sand paper.
It's a technique AFV people use to create texture, but I use it for car modeling quite often.

Thanks for the tip. What does AFV stand for exactly?

welcome cornbread...afv stands for armored fighting vehicle....that means tanks for all you's who've never built any military vehicles. hehehe....

One bit of warning here......check a 1:1 scale version of what you're building before filling those seams. You may discover that there really is a seam.
I dutifully filled and sanded the seam on my Powerglide trans resin master, then bought a Glide for my 1:1 race car and discovered....you guessed it....there's a seam running down the middle of the case.

Well, it's a 65 Cobra S/C. Don't really have one to look at. But, my old F-150's 4sp has a seem. I might as well leave it.