Thread: 4t80E trans swap

In manual mode there is significant engine braking in 3rd gear which is where I need it most as the trans doesn't shift to 4th.
The carbon/ceramic brake pads take over so far no stress at all on the brake pads.

One thing I forgot to ask Dave is which axles do I need. I hear one axle needs to be from the Aurora and the other from the Eldorado ?

We located a 4t80E and a local U pull it yard which means cheap but not garanteed to be good.
It is a Caddilac Deville with the 4.6L Northstar.
I think 75$ for the trans. Car has between 110K and whatever. It has a sticker on the door written by hand 110K miles. in 2012
Drivers seat is in decent shape but looks 130K-150K in terms of wear, that's how I usually tell how much mileage a car really has lol.

What's good about this is I get the axles and everything else I need for the trans.
Not sure if those axles will work directly or not I hope so.

Originally Posted by darkhorizon

I suppose if you left it in 3rd it will enable overrun in 3rd, which gives you engine breaking down to 50mph or so. Otherwise just throw the shift switches and call it a day.

Remember I have TWO engines. I was worried about braking but that was when I didn't have the trans in auto mode.
I have the power of two engines slowing me down

I have surprising braking power, I was shocked. I took the 1st exit at my track vs the 2nd exit for most cars in the MPH range I am in. And that was without effort. I think my braking power can handle 150mph no problem, then I'll have to think Parachute.

So I picked up that 4t80e.

I got most of the info I needed last night.
Found the diagrams for the pinouts and lots of info on the swap coming from Pontiac Jeff and also Dave at TEP.

Now I'm missing the grounding pattern on the shift solenoid for each gear as I have to built my own gear switching device. I'm not fond of paying 1000$ for a trans controller.

Originally Posted by darkhorizon

Only advantage to the shift controller is running the pressure control solenoid really... Max that b!tch out.

I was planning on that. Run it disconnect and max pressure.

There is a shift kit for this trans. It seems to have notoriously lazy 2-3 shift and even a soft 1-2 shift. The kit addresses this but it's more involved and better done when doing an overhaul as far as I know.