[finnbair2020]

94 Sundance transmission. It slips sometimes when accelerating, especially from a stop. It is possible to move the stick from D, 1, or 2 into N without pushing the button. Could the problem be merely with the stick/button

 

[valiant67]

It's not the shifter. A problem there would either mean you were in the wrong gear or no gear which isn't slipping. Slipping is either a low fluid level, really bad fluid, a restricted filter or internal transmission issues.

 

[Bob Lincoln]

It is possible to move the stick from D, 1, or 2 into N without pushing the button.

This is normal for every automatic transmission that I'm aware of.

 

[peterjon1]

The shifter is acting normally.
There can be a problem with the 3 speed auto not shifting properly from a start if the governor is sticking. Can you make it shift properly by moving the shifter manually from 1-2-D as you accelerate?

 

[ImperialCrown]

The button would need to be pushed to go from Neutral to Reverse to Park and again to get it out of Park into gear. Button action isn't needed between Neutral and 1.
As for slipping, how is the ATF level and condition? Has it had any recent ATF and filter change?
If the shifter moves by pushing on the gas pedal, then the kickdown shaft is binding with the concentric (one inside the other) gear range selector shaft on the top of the transaxle.
This was common in damp climates and with the battery mounted above this area, battery acid could mist down and start the corrosion. Once this kickdown lever binds, shift points can be late and variable. The kickdown bell-crank on top of the transaxle should move freely with a light spring return to the idle position. The kickdown return spring should be at the other end of the kickdown cable at the throttle body. Sometimes this spring is missing.

 

[Marcos]

The button is needed to go from D to 2 and further from 2 to 1, but not back. D to N and back does not require the button.

Regardless of the button, there should be a definite detent between positions. If it just slides with no click, then there's something wrong.

 

[finnbair2020]

Thank you for the help. I can see now that the button is acting normally. I've mostly driven standard transmissions... I added some transmission fluid and something to stop slipping transmissions. It's working fine now but I have a feeling I'm looking at replacing the transmission at some point. How difficult would that be?-- accustomed to working on tractors...

 

[B10alia]

You might want to do a fluid and filter change to see if that rectifies the issue. Use some good ATF+4 and a decent filter. The $30 that's going to run you is much less than buying a tx and putting it in. There's also no guarantee that a unit from a pick and pull will work. You may want to look into rehabilitating your current unit. Either way, it can be done in your driveway, harder to access than a tractor tx because of the front wheel drive setup though. I think we should try a bit more diagnostic first, though. These transmissions are extremely rugged and many times, it's a simple issue.