I had a hard time finding a transmission with the 12 oclock bolt, for my 5.3 swap. So I found a transmission at good rebuilding shop to use. The code is 2cbd. So its from a van with a 4.3. The transmission shop sold it to me said it was rebuilt with all the good stuff and gave me a 3 year warranty, no worries.

It has the correct input shaft like the real ls1, no nipple on the end. I plan on using the trailblazer converter. Not a race car just a street cruiser.

The engine is an 2004 5.3 the trans is a 2002.Can I just swap the bell housing for the ls one with the top bolt? I was concerned the bell housing length maybe different. I dont want to use any adapters. Keep the oem flexplate, just change the bellhosing and bolt it on and go. I understand the current bell will work, but i just want the correct one if its that easy.
Thank you

 

Please wait for confirmation from a pro/expert like ClineBarger, Dynamic396 or Bbond105, but I will go out on a limb and say the trans should be fine assuming it has the 300mm input shaft as you say it does. I don't know if the 4.3 bell housing would work, but your '02 should bolt up just fine.
Remember that the bell housing bolts require a T50-PLUS bit. You really need the correct bit, an impact tool and 50 lbs of downward pressure to ensure you don't strip the heads. Perhaps the trans shop could swap the bell housing for you or prove that they are interchangeable.

Lets see if the experts agree or correct me...

 

Off the top of my head, I'd say that mrvedit is correct. The bell housing from your 5.3 will bolt up. That's not an issue... And as long as it has the LS style input shaft (30 spline, no pilot on the end) and the longer stator support, you should be good.

I think I would, just to be sure, put a straight edge across the face of the bell housing on the old transmission, and measure from the straight edge to the end of both the input shaft and the stator support. Now swap bell housings and recheck the measurement. And yes, use a Torx PLUS 50 bit (OTC #6191). It may be a bit difficult to find locally...at least it is in Spokane, WA...! A transmission shop will have one, though.

I'm 99% sure you'll be fine, but GM did some weird stuff sometimes, and keeping that 4.3 around was definitely one of them. I very rarely deal with them...

 

You need a little propane hand torch, heat each bolt head for 20 secs and they come right out.

 

That probably melts the thread lock installed at the factory.

 

It has to.......I hit them with my impact, nothing. Heated one for 20 secs, bam came right out. Tried it with several to verify the heat was what was making them come loose. No question about it.

 

Thanks for the help.