'88-90 Reattas got the 4T60. The rare '91s got the L27 and 4T60-e.
Today I went ahead and installed a large transmission cooler. Fluid was changed about 20k miles ago. I went ahead and dropped the pan, changed filter, added Mobil 1 ATF, and with the return line off did a DIY flush. Add a quart, start it to pump it out, stop, add more, start it...until clean. 11 quarts total. I didn't like the idea of leaving the other 6 quarts up in the torque converter and having to Drivetrain is original to my knowledge and has almost 156k miles, and doing great. Still shifting nice, virtually no oil consumption.
Before I did the project, I couldn't find a definite answer to if swapping the parts would work or not, so I went ahead and took up the experiment
. Thankfully it all worked out.
That computer is the ECC. The Electronic Control Center. Shared with the Riviera of the same era, it'* a touch sensitive mini-CRT. No standard radio. Radio, climate control, secondary gauges (tach, oil pressure, coolant temp, voltage), trip computer, date reminder, optional car-phone...it'* all handled from here. There'* also Service Mode, more of a dealer thing with a special key combination, that can display any trouble codes and also access ECM data (which can help in tuning). There'* a CRT controller module to handle it. One guy made a point that Buick had this ('86, with the Rivi) 20 years before Cadillac did.
The simple diagnostic page
And when you get in or out, it displays its name.