I have a new problem that's poped up. After I'm in overdrive (50 mph and up) about half the time the transmission seems to bog, like it's trying to go into a really high gear. it's worse going up hills and it want's to go in and out, sometimes cycling really fast, almost like a 1/4 second cycle rate, sometimes lasting for a goos couple of seconds before "disengaging". RPM's drop down from the normal 2100 or so at 70 mph to about 1600ish. Any ideas? I'm hoping that my lockup torque converter is maybe just now trying to work after all these years (I don't even know if I have one ).

 

Sounds to me like your "fifth gear" is just your TC lock up like you suspected. Your RPMs at 70 are about what I turn while locked and unlocked with 2.73's so I'm assuming that's probably what you have too.

 

You can easily find out if its the lockup converter by unplugging your transmission. Then drive it and see if it drives like it always did. Do you have a stock converter or a higher stall converter? An drop of 500+ RPM is unusual for a stock converter when it locks up, unless it locked up while under heavy load.

But anyway, if after unplugging it, it drives like you were used to, then it might be the Torque Converter Clutch you might have been feeling. You might have something like a bad brake switch causing your TCC to kick in and out.

 

Is the same brake switch used for the Cruise control? If so, I noticed the other day that I broke mine when I replaced the steering column.

 

!!!!!!!! Sounds like we have a winner! Get the switch fixed and see if it still does it.

 

You guys are awesome. So I take it that the torque converter switch is the same switch used for cruise control?

 

I'm pretty sure, yes.