"1999" Automatic. While accelerating or climbing a grade it shifts perfectly. When you are on the highway and trying to hold a steady speed it go into a neutral state or slip. I have to let off the gas or speed up to make it engage again.
-No leaks
-Fluid is full
-Fluid is red & doesn't smell burnt
-Did scan and there were NO code !!
-While recreating the problem w/scanner on it, it showed it was still in lockup
-Serviced every 20K
Any suggestions would be appreciated!!!
Thanks, Dondobe

 

Serviced what every 20k?

 

I serviced the transmission (fluid & filter) every 20K

Dondobe

 

if mechanically it appears in working order then it sounds like a sensor is either bad or going bad to tell the scanner its locked up but when driven its slips. either a factory manual or shop can show you the bazillion different issues to deal w/. i would start w/ the electrical part before dropping it for a rebuild kit or something else big money costing.