After changing out the stoplight switch why won't the transmission shift?

When you say it isn't shifting, do you mean from park or between gears?

When the trans gets old, if it wasn't serviced on a regular basis, the fluid gets very dirty with old clutch plate material, dirt. They say that with new fluid, the detergents in it will clean off the clutch plates and cause them to slip. Honestly, I've never see it happen, but that is what they say.

I TOO HAVE DEALT W/ "THEY"

USUALLY I CAN NEVER FIND, IN PRINT, MUCH TO BACK UP, "THEY"

IF YOU MISS MAINTENANCE, ON SOMETHING, I HAVE NEVER OBSERVED ANY REPAIR MANUAL, TO SAY, DISREGARD IT!

"THEY" TELL YOU TO DO THAT A LOT, THEIR REASON: IT WILL MAKE IT BREAK/ SHELL OUT.

MY BELIEF IS, NEW FLUID, CAN ONLY MAKE LUBRICATION BETTER

HECK, MR. FILTER MAY BE STOPPED UP TOO!

MY THOUGHTS ARE: IF IT'S GONNA SHELL OUT, IT'S ALREADY DAMAGED OR DARN CLOSE, AND GONNA DO IT ANYWAY!....MY HYPOTHESIS IS NO MATTER WHAT THE FINAL RESULT IS, "THEY" WILL ALWAYS MAKE IT TURN IT INTO SOMETHING "MAKING THEM SOUND KNOWLEDGEABLE"......WHAT EVER HAPPENS, "THEY" WERE RIGHT, OR IT WAS ALREADY TOO FAR GONE!...."THEY" LOOK GOOD REGARDLESS!

SAME GOES FOR IF YOU ARE IGNORANT, AND YOUR RIG BREAKS DOWN, AND THERE ARE 10 PEOPLE STANDING THERE, OFFERING ADVICE....ONE OF 'EM IS GONNA SAY, "IT'S VAPOR LOCKED", THE COOL THING IS, YOU CAN ASK 'EM EXACTLY WHAT DOES THAT MEAN, AND FEW REALLY KNOW....IT'S JUST SOMETHING THEY'VE HEARD SOMEWHERE, SORTA MAKES 'EM LOOK LIKE AN AUTHORITY!

DO YOU NOT CHANGE YOUR TIRES, WHEN EXCESSIVELY WORN?....OR DO YOU JUST KEEP RIDIN' ON 'EM TILL THEY SHELL OUT ONE AT A TIME?

CORRECT, ON TIME, MAINTENANCE OR NOT...WHAT'S GONNA GET HURT, DOING WHAT THE AUTOMOTIVE SPECIALISTS TELL YOU TO DO, TO MAKE IT LAST?

PERSONALLY, I'VE FOUND THAT A FILTER/ FLUID REPLACEMENT, HAS WORKED WELL, MANY TIMES, ON A NEGLECTED VEHICLE

THINK I'M DONE PREACHING

HERE'S WHAT I COME BACK WITH, PLUGGING IN "2WD"

http://www.autozone.com/autozone/parts/1995-GMC-Jimmy-2WD/Transmission-Filter-A-T/_/N-j1v4lZ6o2e7?filterByKeyWord=transmission+filter&fromString=search

USING THE EXACT CORRECT JUICE, USUALLY WRITTEN ON YOUR TRANNY DIPSTICK.....I TRUST THE STICK, MORE THAN WHAT "PETER THE PARTS GUY" MIGHT ACCIDENTALLY TELL YOU, WHEN HE'S BUSY

JUST A WILD GUESS, LESS THAN $35 AND AN HOUR, YOU'LL BE DONE!

KEEP US POSTED

THE MEDIC