trans shifts through all gears,when in overdrive it keeps shifting in and out of O.D .was told neutral saftey switch. has anyone had this problem

 

Pretty common. It could be lots of things. Here's a list to get you started:

Dirty or low fluid
Brake switch
Throttle position sensor
Transmission control module
Shift solenoids
Torque converter

I checked or replaced every one of these, except the torque converter, and the solenoids were the only thing that seemed to have cured it.

 

Thanks Jeremy, I've installed new brake switch,tps,fluid & filter, so i'll try solenoids next. It shifts in & out of OD really fast.Made me think electrial.Again thanks for your list.

 

What year? Is it shifting out of OD or is the torque converter clutch going off and on?

 

I'd assume he has an '88. Just a hunch.

 

Missed that lol

 

yea it's an 88 limited, and no torque converter clutch is normal. have not replaced selonoids yet, will post what fixes it when i find out. Thanks for all replys

 

Are you SURE its dropping in and out of OD? Thats a pretty big RPM change and Ive seen it on here many times where people perceive the ~300RPM drop of the TC lockup as the OD shift.

Do you have the trans switch in "power" mode?

If not, do it and leave it there.

With it in comfort the tc locks at like 35mph which is way too slow, especially if you have bigger tires, etc.

Did you properly adjust the TPS when you changed it? Throttle position has a major role in shift points.


And before someone says it: the TV cable has nothing to do with shift points, although it might be a good idea to adjust it anyway.

 

no i have not tried the power switch but i will, yes it is dropping in & out of O.D.for sure.I will double ck. the tps. Thanks again for all your help!!!!!!!!

 

http://cruiser54.com/?p=54

 

Check the 7.5 amp fuse in the Trans location in the fusebox under the dash so you'll be sure the switch has power to it.

If the switch lights up, it SHOULD be good and try using the Power mode and observe differences.

Adjust your TV cable per the link right below.


also, if you can score an 88 to 90 tCU somewhere they are better controllers of shifting IMHO.