I have a question for anyone much more knowledgeable than I?
Did all of the early J-Bodies have Automatics with lockup Torque Converters? I recenty bought an '84 2000 Sunbird base Coupe. Natural asp. 1.8L.
During driving, I dont feel the transmission locking up above 35 MPH or so. Thank goodness I don't have the issue with one staying locked up!! Was wondering if it didn't have that feature, or might there be a relay somewhere that might need replacing. Any information is greatfully appreciated!! :-)
Sorry... Found the answer in an older post. Should have looked a little deeper.
Re: 84 Sunbird Transmission Help
Sunday, April 17, 2005 9:45 PM
sharkey
the transmission is a th125 or 125c. the diffeance between the 2 is the 125c has lockup, were the 125 doesnt. the way you tell is the front of the trans (front being the part that point to the front of the car). if you see a plug with wires going into it, its a 125c.
The best I figure out is that the transmission has the clutch, but the car doesn't have the wiring, nor the computer to use it.
Both of my J-bodys have the black connector on the transmission housings for a wiring harness to go into. But the 2000 Sunbird
doesn't have the wiring to go to it. Also I did a bit of searching on Autozone.com of the Computer for various models. The Wagon and the Coupe have different computers. I've also noticed the 2000 Sunbird doesn't have a 3rd brakelight, and there isn't any wiring connected to the drivers seat. Sure is nice to have something less complicated, than more so!! :-)
If the transmission has the clutch and wiring, you could setup a manual momentary push button switch to lock it and tap into the brake light switch to unlock it. Look up "latching relay circuit" for how to design that system. You need a schematic where one momentary switch engages the relay and a second one disengages it. Both switches normally open.
You'd have to activate it only above about 35 MPH, unless you're going to be puttering around town and never getting above 2nd gear. I dunno how it would handle upshifts with the TCC locked. The nifty bit with the manual control is your MPG could be better in town than with the automatic TCC only engaging in 3rd gear.
"What is it about pyromania and civil insurrection?" she wondered. "Can't anyone stage a riot without bringing the matches?" Major Serafina Palacios, Imperial Marines
