1985 4+3 disengages

[macgyver]

Overdrive drops out cruising down interstate at any time and then comes back in 1 mile or 10 miles later. Need help on what could be causing this?

 

[vetteoz]

Overdrive drops out cruising down interstate at any time and then comes back in 1 mile or 10 miles later. Need help on what could be causing this?

Checked O/d fluid level lately?

If fluid level OK , then if operation is intermittent after correctly engaging then logical reason would be loss of power to the O/d solenoid.
Flakey connections at O/d relay ( common ) ,

bad / lose connection on wiring from relay to solenoid . etc

 

[macgyver]

Are these right on the overdrive unit or at the ecm/bcm. Where is the signal picked up from? Thanks for the help.

 

[vetteoz]

Are these right on the overdrive unit or at the ecm/bcm.

Relay on firewall
Relay itself may be faulty give intermittent operation

 

[macgyver]

Thanks I will check that out.