Can anyone confirm that the overdrive unit is completely seperate from the other gears and whether it is safe to turn the overdrive unit on while in 1st or second gear? I don't feel like running new wires from the speed sensor to the pcm, so I plan to run OD and converter lockup to switches in the cab. The ratios with OD in other gears don't seem useful , but just in case the transmission decides to shift into 2nd with OD on I need to make sure it is safe.

Is the OD off button in the cab on the power or ground side of the solenoid? I'm guessing its on the ground side since lockup is on the same power wire.

 

NO I would say it is not safe to turn on at the same time. If your positive your problem is in the wires just replace it and do it right.

 

youre opening a hornets nest why would you want OD in 2nd? why are you thinking you need to run new wires?

this trans is designed to run OD only after it runs thru the 1st 3 gears; not a "1st/over--2nd/over" type deal, like a 13 speed semi truck transmission or a gear vendors addon type deal; I dont understand why you would want to do something like this; yes the gear train is seperate for the OD vs the rest of the trans, but there is a 2nd set of clutches in the OD section of the trans that also has to be engaged any time the truck moves; or the truck won't move....

 

I switched from an electric speed sensor to a mechanical after mice ate a lot of my interior wiring harness and i had one from a 92 w/ mechanical speedometer laying around. I looked at the wiring diagrams and it looks like I would need to change the pcm to the 92 to get OD and lockup to work again. But, that means I also would need to change to the 92 fuel rail and fuel pump since fuel tables would be off with different injectors and fuel pressure. Who knows what else would be wrong after I changed to a different pcm. I would rather not get into it since I plan to get a 5 speed in the spring and all of this won't matter anyway.

 

no you would not have to go back to the 92 fuel rail... you can mix match computers and trucks 92-95 as long as engine and trans is right... I have a 94 computer in my 93 from when I swapped from auto to manual 94 is 1st year returnless 93 is last year return style; there is no pressure sensor to tell the computer what the pressure is, as long as the O2 sensor is satisfied with air fuel ratio the comouter is happy no matter the pressure in the line... computer controls on/off time of injectors. not pressure.
another difference between 93/94 is 93 is last yr for cable drive speedo, half that sensor is still electronic to satisfy the computer other half is mechanical cable drive
as long as the speed sensor has the electrical plug you should be good to go, mechanical cable or not.

youre making all this harder than need be