Let the fun begin. 4L80E/205 build up
 

Today I got the parts required to begin modifying the early figure 8 205 to hook up to the 4L80E. After a little digging, I decided not to buy the conversion kit as a whole. I already had the seal kit, and after a couple phone calls, I was able to purchase a new short 32 spline input and bearing for $115. Then I purchased the Advanced Adapters casting buy itself for $300. Complete seal kit was $25 locally so right now I am up $175 over AA's kit cost and $300 over ORD's kit. As soon as my machinist buddy gets home in a couple days, I will get the transfer case machined and start assembly.

Re: Let the fun begin. 4L80E/205 build up
 

Mike,

That is cool! Please keep us posted on this project. What are your plans for a transmission controller? It looks like you got a real good deal on the Advance Adapter piece, as I have only seen 4L80E/ figure 8/205 adapters from them in the $500 range. What machining do you need to do?

I am a manual trans freak for my type of off-roading (mountain trail riding) but I am also hard up for overdrive given the gears that were just installed. I have a 454HO in my truck now with a SM465 that I am looking at EFI’ing using a marine L29 intake (a brand spankin new piece that I bought on Ebay a while back) operating on a MSD MEFI4 controller but will still have a direct drive trans. I also have two 8.1L big blocks (2001 and a 2005) in my garage, one 2wd 4L80E and 1 Dodge 4x4 variation NV4500…..all of which are broken but can easily be fixed.

Crunching numbers, I cannot decide which will be more cost effective to fix…….EFI the fresh 454HO and live with direct drive, fix the NV4500 for the 454 or fix an 8.1L and bolt it to a 4L80E. The 8.1L will not work with the NV4500 easily nor will the 4L80E work with the MSD engine management controlled marine L29. I also have a lead on an Allison 1000 to screw to the back of an 8.1L but transfercase options with a right side output shaft are non existent other than the electronic shift piece of crap that is currently found in the current GMT560 4x4 Topkick’s and Kodiac’s and nobody makes a 205 adapter for the Ally yet. What's more, I doubt the Allison will fit under the truck w/o a body lift. I do not believe in body lifts…PERIOD.

I prefer a manual trans but a 4L80E juice box with an 8.1L may be the all around easiest conversion to obtain both EFI and overdrive at the same time and put the most HP to the ground…..but the 4L80E adapter to the 205 play a big part of the budget. My truck was originally an automatic so going back to a juicer would be somewhat easy.

Wheww, sorry….that was a confusing concoction of options….

Keep us posted on your project.

Re: Let the fun begin. 4L80E/205 build up
 

Yes, please keep us updated. I am thinking about doing the 4l80e conversion in my blazer. I was also thinking about getting an atlas II T.C. to replace my 205 but that is alot of coin.

Re: Let the fun begin. 4L80E/205 build up
 

Awesome combo!

Gonna watch this one. :)

*click* to subscribe.

Re: Let the fun begin. 4L80E/205 build up
 

Larry, I bought the adapter only from AA, and it is only $300 or so by itself. Actually the ORD is a little cheaper by itself but I had my questions answered better by AA, so I bought theirs. The kit is you buy it from AA is $621, and I was quoted $770 from ORD. I will more than likely be using a Powertrain Control Solutions (PCS) controller. They are about $800, BUT what they have is they can accept a secondary signal for a different gear ratio when in 4 low, so it should operate properly with the 205 engaged. It is also simpler to use a 2wd tranny because the tranny has to have a VSS internal and not all 4wd one have that I have found out. I have also already picked up the full spline output shaft for the 4L80E for $75 which appeared to be a new take out.

Mike

Re: Let the fun begin. 4L80E/205 build up
 

Mike,

That is a good deal on the adapter but crimany, that is kinda steep for a trans controller. Who cares what the speedo is reading while in 4 low as long as that signal is not going back to confuse the controller and trans performance? Your correct…the 4wd trans actually have the speedo VSS signal picked up in the Tcase whereas the 2wd’s are near the output shaft, which is non-existant on 4wd applications anyway....as, the VSS is moved to the Tcase.

Another more cost effective option could be to use a late 90’s through 2001 naturally aspirated 6.5L diesel GM/Workhorse P-Chassis (Frito-Lay type truck) TCM and wiring harness for a fraction of the cost of the PCS controller to run the 4L80E behind any engine. The TCM’s in that truck platform of that era are basically the same old OBDI style aluminum box ECM (that was used in GM TBI cars and light duty trucks for years prior to 1996) but it only controls the trans functions with the proper wiring harness and PROM, as the non-California 6.5L diesels were non computer controlled. You would need a TPS input to sense load and whatnot to make it work but it is a pretty simple system. The PROM inside the ECM (TCM) of that era of P-chassis is programmed specifically to the tire size and gear ratio. Pretty much old school technology but it works well and it could be a cheaper option for you. The down side is there are only a handful of PROM options for gear and tire size combinations that may or may not be hacked into and modified by the aftermarket automotive electronic geeks, such as AZ Speed and Marine. The P-chassis stand alone TCM is another route I often entertain if I ever decided to go the MSD MEFI4 EFI system on the 454 with a 4L80E.

BTW...I also have a buddy a that works for AM General in Livonia, MI that validated a stand alone trans controller in a non-military spec Hummer H1 6.5L diesel platform without success a few years ago. I am pretty darn sure it was a PCS contoller that he was playing with. If I remember correctly, he mentioned issues with calibrations with detent shifting and speed of upshifting as well as OD engagement. That was a few years ago so their technology could have been a little less refined at the time plus the Hummer was a hacked up test mule as most test mules are.

I work for a truck manufacture as well and am always looking at our current offerings to pirate parts numbers from to bolt modern technology onto our old rigs.

Re: Let the fun begin. 4L80E/205 build up
 

I have alterior motives for the controller as well......

PADDLESHIFT

Re: Let the fun begin. 4L80E/205 build up
 

Her is the before machining, during machining, after machining, and after I finished installing the intermediate and front drive gears. Hopefully I can finish the rear drive by the weekend.

Re: Let the fun begin. 4L80E/205 build up
 

That there is a purty transfer case,Mike :sexy:

Re: Let the fun begin. 4L80E/205 build up
 

Ooh! Shiny!

Looking really good man!

Oh, and DirtyLarry, you can easily bolt an NV4500 up behind an 8.1L, just use an old 396 or 427 neutral balance flywheel with a 10 spline clutch disk, and a stock 396 / 427 pressure plate. They bolt straight up to the 8.1L's crank, which also happens to be spaced the same as the earlier generation engines, and you can use an Advance Adapters bellhousing with an old Z-bar clutch linkage :)

Re: Let the fun begin. 4L80E/205 build up
 

205 is 95% finished, just need to bolt up the adapter and get a different shifter out of a later truck. Now on to the tranny. Had to completely disassemble to install the special output shaft. So while I am at it, naturally I decided just to go ahead and rebuild it while it was down like everything else I touch. One thing I can't do is leave anything I touch alone. :crazy:

Mike