1996 silverado z71 4x4 overdrive doesn't work

[chevy69man07]

I have a 1996 silverado z71 4x4 overdrive doesn't work even at 55 or 60 mph. wondering what it could be.

[j cAT]

Originally Posted by chevy69man07

I have a 1996 silverado z71 4x4 overdrive doesn't work even at 55 or 60 mph. wondering what it could be.

this is a very common condition with high mileage vehicles using dexron III. what occurs is the valves are worn causing the pressure to drop. this then will cause the loss of the 3/4 od to operate.

bring to a transmission shop to verify and if you do this soon you may save the transmission from more damage.

make sure they install dexron VI only. do not use any fluid called dexron III or what ever they think is correct.

torque converter should be flushed out.