a while backI had a few topics posted on here that were asking for help with tranny troubles. Specifically I had no tcc lockup and a really harsh shifting problem on a 2000 GMC Sierra 2500HD 4X4. Thought I'd share the results with everyone in case they had the same issues at some point. Both problems were related. The harsh shifting was caused by the trans going into a default mode where line pressure was commanded to maximum and shift patterns were made to factory presets. This resulted in tire-chirping shifts in ALL gears, including overdrive. The cause of that?? A code was set for "transmission component slipping" at highway speeds. The actual problem?? A 30 cent o-ring on the turbine (input) shaft of the transmission splitcausing the convertor to not lock up at all since no pressure could be applied to the tcc, thereby setting the code. I had FOUR transmission shops do diagnostics on this transmission to find the problem, and they all had the same answer....time for a rebuild to the tune of $2400 or so PLUS R+R. All shops stated they had checked everything and this was the only option. I finally got my hands on a scan tool and checked everyhting for myself. Yesterday I did my own R+R, replaced the o-ring, converter (rebuilt), front pump seal (because I was there), TCC apply solenoid (for good measure) and a fluid and filter change. Total cost?? under $300.00, not including my time (6 hours). Moral of the story?? Two of the shops were places I had dealt with before many times and I trusted them, BUT when something doesn't seem right question it. I do want to thank everyone who offered advice and tried to help. I also want everyone else to remember this lesson!!!!!!

 

Nice[sm=interesting.gif]

 

just goes to show how a SHOP will just quickly assume a major problem and go through unessecary processes. idk if thats cause they get all makes and models or just cause theirs the want for the money. not knocking dealers here but shops.

 

That is why I always either check stuff for myself or have one of my friends (motor heads)check it out. Ive been burned by too many shops for simple stuff that i could have done if i had just taken the time to check it out.

Good for you for checking up on them!