4L80E/NP205 swap

[bilfman]

Hi peeps,

I just completed a 4L80E/NP205 swap and am going to go through the build here in the forums. I looked on the net many times and couldn't find a 'real life' start to finish of a project like this. I replaced the TH400/NP203 in my 1979 crew dually.

The basics of my dually are it is a 454 with hooker headers, edelbrock performer, edelbrock 750cfm carb. Diffies are dana 60 up front and dana 70 in the rear. The 60 has a eaton tru-trac locker and the 70 has a detroit locker and I am running 3.73 gears. I was running about 2600 rpm at 60 mph.

In 1991 GM released a 4L80E/NP205 combo this was only available in the crew cabs, which were still square bodies in 1991. These are very hard to find, but I was able to locate one for a steal of $600.

I have done many resto in the past 30 years but the electronic transmission had me a little worried. For those of you who feel as I do, I can tell you now it is a piece of cake. As you follow the build you will see how simple it really is.

The trans and tcase looked rough under 21 years of grime, but to me it was a diamond ready to be worked. Here are some pics of the beast when it arrived.