700 torque convertor lock up

[obijuan]

how does the lock up activate? is it a wire or a vaccuum? the local tranny shop says i dont have lockup on my TC. do i need lockup with 35" and 3.08?
thanks

 

[84 K5 4x4]

Hey i got a 700r4 in my blazer and lockup helps on the highway but with 3.08 gears you probably dont need it. there is a kit out there that is about $100 it comes with a silinoid that screws in the passenger side of the tranny and wires up for lockup it makes a big difference about like having a 5th gear. Anyway i think depending on the year....that there is a vacume activated silnoid somewhere around you brake booster that has a wire that runs down to the plug on the tranny. But the kit is the way to go.

 

[4X4HIGH]

The lock up is done electrically and it needs to be hooked up or you'll kill the tranny. Actually with 3.08's and 35" tires with the 700R4 it isn't going to last long anyways.

 

[obijuan]

whats a better gear ratio selection for highway to sort of extend its life?

 

[Moody]

At a minimum 4.10's....although with 35's 4.56's would be better.