Well, I already got a response from Andrew Schreck saying that he was forwarding my email to a colleague at GM Powertrain. I just didn't post it because it didn't offer anything in the way of an answer. Whether this other guy responds or not is another question, though. I guess time will tell.

at least you got an intial response. WE need a GM 4T60-5 engineer on this site

well I work with 4 L 60-65, if that helps

Well mkaake.....tell us what YOU know about the MN7.

We already know about the weakness of the stock open differential.
We have heard about the 3rd clutch weakness.
And also about the weakness of the input shaft unhardened splines.

Yes, yes.... do tell, do tell! Just don't get yourself in trouble with the General. I still haven't received a response from a GM Powertrain specialist. I guess I ought to give him a little more time, eh?

unfortunately, knowing about the L'* doesn't mean i know all about the t'*
i try though. i've got the manuals, but don't work around FWD people. if luck is with me, sometime w/in the next couple of months i'll be able to attend a 4t65 teardown class to learn more about it. usually the people who put on those classes know exactly the info you're looking for. When I went to a one week class on the L65, the guy was telling us how to increase performance, week points, what would be overbored on a VB, etc...

That would be outstanding, man. It'* always great to have an "inside guy" to help with technical stuff. Like I've posted before, one of the members of the Thunderbird and Cougar Club of America is an engineer who designed some of the Ford RWD transmissions. Of course they have more members and are more widely known than us, but it sure would be nice to have that kind of expertise on our side. Your assistance would be great, mkaake.

ok i think u have a way higher chance of getting the info. here is a video i saw on gms site... http://www.gm.com/company/racing/mov...esentation.mov

and the car at bonneville may have different trans mods... heres another url http://www.gm.com/vc/performancedivi..._red_line.html

There is hope for our transmissions.

the article says that it uses the 4t65-e trans... unless thats a typo that means that probly all the parts changed to get a hd are not strong enough to hold anyway... so they would still have to be changed