Consideration #6: gear shift setup
My car was originally a 3spd column shift automatic. I wanted a floor shifter, and I wanted it cheap. I went junkyarding and found a FWD Grand Prix with a floor-mounted 4spd shifter (meaning it had a detent for 1, 2, 3 & D). I grabbed it and bolted it to my floor. That car's shifter cable was plenty long enough to route forward through the firewall, then down to the transmission.
As you might guess, this shifter cable wasn't designed to operate this transmission. I was determined to make it work. The cable was determined to fight back. In the end, I used a small L-bracket to hold the cable to the bell housing so that the cable can operate the shift arm. Well, it
sorta operates the shift arm. It shifts smoothly through P-R-N-D, but then the angle gets funny and it doesn't want to shift down into 3 or 2 or 1. This is all I
need to operate the vehicle, so I've just lived with it... but it really bugs me. I'm probably going to have to bite the bullet and spend money on an aftermarket shifter eventually. You might want to do that up front.
But whichever shifter you decide to use,
DON'T do what I did and wait to install it until after the transmission is in the car! I was worried about the cable length, so I waited to make sure it would let me mount the shifter where I wanted it. Eventually I drilled four holes in my transmission hump, then went to bolt in the shifter. The two rear bolts were not too difficult to install. The front left bolt was very tricky, and I needed a neighbor kid to help by attaching the nut from inside the car while I was lying underneath the car holding the bolt in place. The front right bolt was just plain impossible; there was so little space between the top of the trans and the tunnel that I could not figure out any way to maneuver the bolt into the hole from under the vehicle. Oh, well; three bolts will have to work. Be smarter than me--install your shifter while the trans is out of the car.
One other failure with my shifter setup is this: currently I am in no way interfacing with the neutral safety switch. This means I have no reverse lights. It means I can shift my car out of Park without having my foot on the brake. It also means I can start the engine while the transmission is in gear. That last fact will likely cause me problems when I visit a drag strip and try to pass their tech inspection, so I will need to address this shortcoming soon. (I am working on finding the NSS wiring diagram so I can craft solutions to this problem.) Just one more thing you should think about when contemplating this swap.
Consideration #7: transmission controller
In case you didn't know, the
E in 4L80E stands for Electronic. That means this transmission requires some sort of computer to operate it (unless you convert it to a manual valve body, but I didn't want to go down that rabbit hole). Because my engine is carbureted, I needed some sort of standalone controller. You have a variety of controller options. After
reading a comparison test in
Car Craft magazine, I decided on
the TCI EZ-TCU. I mounted the TCU on my inner fender:
This unit comes with very detailed instructions, and installation is very easy. They even give you a handheld controller for the initial setup (no laptop computer required!) and to make programming changes at any time. You don't need to leave the controller plugged in at all times, but I chose to do so in order to use its screen to monitor the trans fluid temperature. For the curious, there are two live data screens you can monitor; here is a picture of both of them:
I'm still not a compensated endorser, but I
really like this controller. Setting it up is a snap; you just enter your trans type, R&P ratio, tire size, do a TPS calibration, then you twist the key and start driving. Out of the box, its stock programming suits my driving personality very well. You can customize to your heart's content, telling it to change how soon it locks up the converter, or to shift firmer (or softer), or how aggressively to hold gears before shifting, etc. For example: out of the box, the default programming does not let the converter lock up before 50 MPH. With my 3.08 axle ratio, I thought that was fine. After I re-geared to 3.55, I decided I wanted the ability to lock up a little sooner, so I changed that down to 45 MPH just by pressing a few buttons. Easy.
The EZ-TCU also offers numerous additional 'hardware' options, such as support for a normal/performance mode switch, support for paddle shifters, and more. It does everything I want it to do, and yet I feel I'm not even using half of its capabilities. I just don't think automatic transmission control gets any better than this.
Consideration #8: speedometer
Before doing my engine & trans swap, I had already installed an AutoMeter GPS speedometer in my car. However, it had some quirks that I didn't care for. After the swap, the speedometer suddenly began getting electrical interference and worked very erratically (when it worked at all). At that point, I swapped it out for a more traditional AutoMeter electric speedometer. The TCI EZ-TCU gives you a loose wire with a speed output signal, so all I had to do was connect that to the input wire on the new unit. Done.
Anyway, that's an overview of everything to consider when deciding to drop a 4L80E into your G-body. Did I miss anything? Do you need additional clarification about how I did something? Just let me know. OTOH, if you installed a 4L80E into your G-body and you want to explain how you did something differently, please post away and show us what you did. I'm sure we'd all love to see it.
🙂
