Help! 4+3 trans

[86vetter]

I have a 1986 vette with the 4+3 trans.1)When it is cold out it takes about 3/4 mile before it goes in to overdrive.2)It will only change to overdrive when the shifter is in 1st gear.3)It will only go into overdrive in other gears when you hit the button hard a couple of times.I'm going to order the filter and gasket,but i wanted to see if anyone else had this problem.Thank you for any input

 

[tomcat 74]

I have a 1986 vette with the 4+3 trans.1)When it is cold out it takes about 3/4 mile before it goes in to overdrive.2)It will only change to overdrive when the shifter is in 1st gear.3)It will only go into overdrive in other gears when you hit the button hard a couple of times.I'm going to order the filter and gasket,but i wanted to see if anyone else had this problem.Thank you for any input

Hello, I had some issues with my 4+3 when it was cold. I change to Synthetic gear lube, no problems since. That was 15 years ago. The person I sold the car to says there has not been any isssues with the 4+3.

Tomcat 74
91 ZR1 #906

 

[muddywaters]

I have a 1986 vette with the 4+3 trans.1)When it is cold out it takes about 3/4 mile before it goes in to overdrive.2)It will only change to overdrive when the shifter is in 1st gear.3)It will only go into overdrive in other gears when you hit the button hard a couple of times.I'm going to order the filter and gasket,but i wanted to see if anyone else had this problem.Thank you for any input

Hi, I'm pretty sure engine temp. must be over 120 degrees for the O/D to engage, that's the way my 88 works, you moght have a bad switch and your over drive uses ATF and I would advise changing the ATF. Note the magnet when you remove the pan, if it's loaded, it's been a while.

 

[vetteoz]

)When it is cold out it takes about 3/4 mile before it goes in to overdrive.
2)It will only change to overdrive when the shifter is in 1st gear.
3)It will only go into overdrive in other gears when you hit the button hard a couple of times.

Different year models have different min temps before ECM will engage O/d. See
Doug Nash Overdrive Comparisons
Fluid and filter should be changed @ 12,000 .
Syn fluid not recommended for O/d ; just regular Dexron III .Many have changed to syn on used trans only to find leaks appearing as the thiner fluid gets though places the regular didn't

Most likely your O/d switch at base of shifter is faulty or has loose / bad wiring $5 fix
RadioShack.com

Most of the now reported 4+3 problems are due to old age and lack of TLC , more so to do with the control side of things.Faults in hard parts have long been fixed or the car would not still be on the road

Check relay wiring on early cars ; this is common causing shorts or non operation

 

[86vetter]

Different year models have different min temps before ECM will engage O/d. See
Doug Nash Overdrive Comparisons
Fluid and filter should be changed @ 12,000 .
Syn fluid not recommended for O/d ; just regular Dexron III .Many have changed to syn on used trans only to find leaks appearing as the thiner fluid gets though places the regular didn't

Most likely your O/d switch at base of shifter is faulty or has loose / bad wiring $5 fix
RadioShack.com

Most of the now reported 4+3 problems are due to old age and lack of TLC , more so to do with the control side of things.Faults in hard parts have long been fixed or the car would not still be on the road

Check relay wiring on early cars ; this is common causing shorts or non operation

Thank you for all your input

 

[86vetter]

4+3 tranny

Thanks for all your input,and I'll try those few things.This is a very good and knowledgeable forum