There is a bearing, like a pilot bearing, in the output shaft of the transfer case. The output shaft in the front extension housing is machined to fit into this bearing. When you go into 4H or 4Lo a collar locks the output shaft of the transfer case to the output shaft in the extension housing...
You not crazy. I've towed a number of trailers with my 40. A pop up trailer is no problem, but like Frank said, crosswinds can be exciting. Just take it easy and allow a little more room to stop.
When you order the kit they ask for all the specifics about your engine, trans, rear end ratio and tire size. Then they custom burn an eprom for your application. You can send it back in case you need something tweaked for your application.
I've been happy with mine so far.
I've been running a Howell Universal V8 TBI system for 4 years and its been great. I like that they use all GM parts, so that if something does go belly up you can pick up a replacement anywhere.
For the price you really can't beat it.
When I ordered the Howell TBI system for my 40 they wanted to know everything about the engine (cam specs, compression, valve size, cubic inches), the transmission, rear end ratio and tire size. They took all that and custom made an E-Prom for my application.
If you're running a Howell system...
I have a 4"lift, extended shackles, and 36" IROK's, The roll cage clears the the garage opening by about an inch. I have to use vise-grips to hold the garage door high enough for the 40 to fit under.
Its a bit tight but it beats leaving it outside.
Installed 4x4 Labs "Frombe" steering arms plus 1 ton tie rod ends and very heavy duty tie rods.
Replaced all the front axle hard brake line with braided stainless steel lines.
Do the "frombe" arms clear the backing plate to caliper brake line? I been wondering if folks have modified the brake lines or if they fit fine and this is a non issue.
Cheers