700 r4 chevrolet transmission question

[huckelberry]

Hey, my dad has an '85 chevrolet with a 700r4 transmission that will not go into overdrive. It, the trans was rebuilt a few years ago by a friend that works at the chevy dealership and when my dad put it back in he thinks he did not reconnect whatever it is that makes the transmission go into overdrive. My question is is it a switch in the steering coloum shift selector that could be bad or is this one of those better leave it alone in the valve body things. If anyone can give me a good starting point it would be appreciated.

Thanks

 

[david_r]

Re: 700 r4 chevrolet transmission question

new torque converter too? ............. after rebuild.

has it never worked since the rebuild or just recently occurred?

 

[huckelberry]

Re: 700 r4 chevrolet transmission question

Has never worked since rebuild and he reused the torque converter

 

[Splat]

Re: 700 r4 chevrolet transmission question

Let me think back, Two things to check.

There is a 4 pin electrical connector on the back of the trans. Make sure this is connected and that you have a good ground going to this. This controlls the torque converter lockout internally on the trans. At a certain speed this will create a 1:1 between the torque converter and transmission. If that is not engaging propery you won't feel overdrive.

Also make sure the De-taunt cable is attached and adjusted correctly. I had a 700r4 on my old k-10 plow truck. One night the de-taunt cable broke and created all kinds of shifting problems.

Hope this helps.

Bill

 

[huckelberry]

Re: 700 r4 chevrolet transmission question

Hey guys, Thanks a lot. This will get him going in the right direction.