'94 4L80E to '90 700r swap question

[madcatter]

I know doing a conversion like this, and asking about it with my first post raises it's own questions about my intelligence, BUT, it's happening anyway.

So, I have a 1990 K1500 that's been slowly getting built up over the years, it does most of my towing and hauling. A couple years ago I dropped in a good reman 700r4, which only has about 10k miles on it now. I'm in the process of building an engine for this truck and it'll be going in with a 3500 5 speed once all my ducks are in a row.

I also have a 1994 K2500 burb which the wife will be driving and it never tows anything. The 4l80E dumped reverse a couple years ago and we parked it, but now the kids are getting bigger and we need it back (2005 Grand Prix for sale...).

So, I have a heavy duty burb that doesn't need a heavy transmission and a truck that has a transmission to donate.

Right now, they're both in the shop, both transmissions on the floor.

The speedo isn't a concern yet, the burb is 8 lug 4.10, the truck is 6 lug 3.73 but I'll be swapping all the axles eventually anyway.

SO, what kind of wiring headaches am I looking at. Will the '94 computer work. I can tab the throttle lever for the TV cable no problem, but what needs to be done jumping down from the 11 pin to the 4?

-N8

 

[madcatter]

Really, nothing?

-N8

 

[madcatter]

Ok, so I've determined the switched ECM ground, (pin D tan/black) on the 700r4 trans is (pin M purple) on the 4l80E

And the 12v switched power from the brake light switch (pin A purple) on the 700r4 will be tapped into the old 4wal ABS harness (pin C purple). the ABS module quite before we even bought the truck so it's unhooked anyway.

SO, that's 2/3. The only thing holding me up now is a finding a 4th gear signal from the Suburban to connect to (pin B green) on the 700r4.

Also, I haven't dipped into the 2 wire vs. 3 wire transfer case connector yet. I know the third wire on the newer case is a low range signal for the transmission. I'm sure I don't need it, can it be left unhooked.

Ultimately I'm just trying to avoid driveability issues, I know the trans will work without any wires but I want it as efficient as possible, as cheap as possible. Everything is bolted in right now, the drive shaft is about 1.5 inches short but it'll drive itself out of the shop until I get that replaced, the TV cable is set up. Basically, electrical is the only hurdle left.

Help me out, please

-N8

 

[madcatter]

As it is right now, I left the wiring out of the equation completely. Everything works perfectly fine. No idiot light, engine runs fine, transmission shifts fine. I'll have to get around to dealing with the lockup eventually since it'll bother the hell out of me if I don't. Otherwise, smooth sailing for well over a week now.

-N8