Well, after a few weekends of gradually putting on more miles on the car and working on the driveability tune... something has gone wrong with the transmission.
Here are the details on it, so any transmission experts can chime in.
Triple edge performance was pretty sure he had used a 2001+ transmission for my core. Last year (or the year before?) I picked up another late model 4T80 from the junkyard, and it's been just chilling. This is important later.
We’ve been putting some street miles on the swap (all 45mph or less, no highway yet) to do cruise tuning for the engine and monitor the transmission.
The temp of the transmission never went above 170. We’ve put on about 20 miles, with the only issue being the transmission unexpectedly downshifting at one point for a few moments then up-shifting again (we were cruising on flat road, throttle position hadn’t changed).
Last weekend when we returned from our lap, I checked the transmission fluid level and it was still on the “check cold” marker, so I added two more quarts – we figured after 20+ minutes of driving it would have been up in the “check hot” spot.
Today we go to do the next round (Transmission temp never got above 145 for this trip). a half-mile down the road, we hear a whining sound. I left off the gas, then resume, the sound goes away. It comes back as we slow/speed up. We head back home, check fluid, and it’s almost to the top of the neck. We check the transmission lines going to the radiator, and it’s very warm, and the lines going back were slightly warm.
We figured I overfilled it, aerated the fluid, and that caused the issues. We leave the cap loose and let it sit for a few hours, then use a fluid pump to pull 2 quarters of fluid back out.
We start it up, back into the street, and it won’t go into gear. Any gear. Putting it back in reverse also does nothing. I shut the car off, restart it, same same issues. While watching the TCU on the laptop, the TCU wasn’t seeing any request come in for it to go into any gear. We shut it off, unhook the transmission pigtail to get it to go into “limp home” mode, which it does, and we get it back to the garage.
Here’s where it got worrisome. As we were testing it (we were constantly checking fluid levels and watching the transmission fluid temp), when it warmed up enough (around 150), even “limp home” mode stopped working!
We shut it down, let it cool off for a few hours, left the harness disconnected, limp home mode worked and we moved it to it’s parking place for now.
While we were waiting for it to cool off, we start looking up teardown videos on the 4T80, because hey! We have a donor!! Mike says that we're looking for a pressure manifold switch. We watch the teardown video which is of a late model 4T80, and it doesn't have it, just the shift selector switch. Odd. So we look at the pigtail on my junkyard transmission, it has more pins than the pigtail on my transmission. So Mike thinks I have an earlier 4T80, which does have this pressure manifold sensor.
So I'm going to order the pressure switch and two new solenoids, I also emailed Triple Edge Performance and gave them the above info, asking for any insights.
This sucks.
Next thing, I finished rebuilding my headlights with 60mm buckets that were offered by someone on the Fiero Forum I'm part of. I get everything installed.... and the headlight cover on the passenger side collides with it when closing the hood, scraping through the powdercoat. *sigh*.
I texted the vendor and he was very kind in giving me some ideas and asking for more information. At the end, we discovered the bucket itself needed to be 'bent' to move it over. I have no idea how it was bent off from it's intended center to begin with.
For now we are leaving the headlight covers off, partially so we can make adjustments to everything else with the hood/lights, and partially to help let hot air vacate the radiator area for now.
We also can't find the instrument cluster we saved out of my car, so I used the cluster from the donor car (which is missing the RPM needle), and hooked up the connections and bolted it in place today --- mainly so I would have mounted switches for headlights and trunk popper, and could see my fuel gauge. For the near future, speedo and temperature information is going to come from the laptop talking to the FAST and TCU. Mike has a car laptop stand that he thinks he can adapt and install as a temporary measure, and he has a car power inverter he can loan me.
So yes... this interior is almost exactly how I was expecting to show up at Carlisle (just wanted to get the horn working)... and likely this is how it will show up this way at the 40th. I *might* have time to add interior door panels and install the awesome 3D Printed skeleton I have.
Last thing that threw me off when I was testing the headlights. I hit the switch, they flip up - yay. I turn them off. They go down a little (maybe 10% of the way?) PAUSE for about 2-3 seconds, then finish going down. The headlights both do this at the same time (so at least it's uniform!). So that's weird. I guess as long as they work!
