A few months ago, my automatic (95 2wd xlt) stopped upshifting out of first. Fluid is fine. I've gone thru the shop manual, and practically memorized every sensor that feeds the PCM computer. I get codes 646 & 647 which refer to "incorrect gear ratio" -- not much help. The other day I connected LEDs up to the wires that feed the selector solenoids SS1, SS2, SS3, so I can watch what the computer is telling it to do. The LEDs come on to match what "feels like" the correct shift points, but the actual shift doesn't occur then. I can "force" an upshift by letting up on the gas slightly, so I've been driving this somewhat crippled beast OK. I'm wondering if there is a "limp home" mode that takes over hydraulically if the computer somehow totally fails, and that's what I'm driving on? Any ideas there? I'd be willing to pay to have it fixed if I thought I could trust any repair shop to be smarter than my potential. Regards, Don

I think we talked about this in either this or another forum. I can't remember the name of the part but it used to be a vacuum selonoid/diaphram. But it controls the shifting. Someone pop up if you remember the name of this thing.

Don