97 Tahoe - did a simple trans flush (dropped the pan, clean the area and filled it up with fluid) - I know it doesn't get all the fluid. Now putting the gear selector in Drive does nothing, but moving to 2nd or 1st does work. No codes at all - checked several times. Doesn't seem to be limp mode since it gets nothing in Drive position and no codes. Does this trans require software flash after changing the fluid? Was not slipping before the change. This is the main vehicle so I could use some ideas. Thanks!

 

Did you change the transmission filter (assuming you have the 4L60E)? No software flash is required for just a fluid change. Yes by only dropping the pan, ~30% of the fluid was changed and technically it is not a flush.

As far as troubleshooting:
- Did you hit the soleniods while completing the work? Check those connections.
- So "D" does not work. What happens when you use "3"?
- Is there enough fluid? How did you check it?
- What kind of fluid did you use?

 

Check the linkage to ensure it was not bumped or moved out of position.
What prompted the fluid change, was it acting up? if so the fluid change may have been the final blow...

 

^ this.

 

I disagree. I think you didnt put the filter O ring in properly and you have no pressure in the case because of that. Drop the pan again, recollect the fluid and check if the O ring is there or moved.

 

Where are the shift solenoids on this trans? I can drop the pan and chk the O ring and check the linkage. But don't know where the solenoids are...anybody got a photo or diagram? Thanks all!

 

My 2 cents. If the only transmission fluid change performed during the life of the vehicle was just dropping the pan, then that would be a problem which may lead to clogging the internal pathways and affecting shifting.

By not changing all/most of the fluid each time, degraded fluid/dirt will accumulate in the converter and internals. When those accumulations dislodge, they can block internal pathways. Yes, some have reported transmission issues after flushes, but IMO those were either not optimal (used cleaning fluid, pressure, equipment, short duration) or perhaps completed too late in the tranny's life.

Just to rule out a few things, please answer the below:
- Did you hit the soleniods while completing the work? Those are on top and not likely, but just in case check.
- So "D" does not work. What happens when you use "3"?
- Is there enough fluid? How did you check it?
- What kind of fluid did you use?
- As in In2pro asked, issues before and is that was promulgated the change?