TahoeTruk
TYF Newbie
- Joined
- Feb 10, 2016
- Posts
- 12
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In depth q here. Have a 2012 tahoe 4wd 6L80 that was experiencing harsh shifts and even that lunging forward sensation when going slow where it felt like my car was being hit from behind. I drive for uber so this wasn't acceptable. To fix the transmission shifts, I went ahead and added half a bottle of seafoam trans tune (which boasts that it isn't a leak stopper, just will free up valves?), and within 5 min of adding it, shifting got much better. Unfortunately, about 20 min later, the throttle began sticking horribly. Its most noticeable in low gears like first and second, and when you take ur foot off the accelerator, it stays at the same rpm and continues to move forward with the same velocity for about 3 seconds(Also i will add if you get going a good speed and shift the car into neutral and let it coast to a stop, the throttle jumps from 550 to 1000 every few seconds until the car comes to a stop. Also if you rev it in park or neutral, it takes longer than normal for the idle to return to 550). As per the instructions of seafoam, I changed the atm fluid within a 100 miles of adding it, so I had the fluid completely flushed and even dropped the pan and changed the filter. It didn't do anything to mitigate the throttle sticking. The harsh shifts have subsided, but they have been replaced by this throttle sticking, which is just as dangerous. To rule EVERYTHING out, I changed the throttle body (which was BLACK-i'm guessing previous owner had an over oiled K&N), so I changed the entire throttle body, changed the MAF sensor and even changed the accelerator pedal. Nothing has an affect. So logic would indicate that something changed when I added the seafoam and possibly something was stuck in 1 transmission valve to cause the harsh shifts, moved through the valve body and is now sticking in another valve that's causing the throttle to stick. Is this even physically possible? Can a clogged or leaking transmission valve cause the throttle to want to maintain its current RPM? Has anyone ever heard of this and have any ideas for a remedy? Is the only thing I can do is have the tranny dropped and valve body opened? Does anyone familiar with the 6L80e have any intuition what valve I should start by looking at or ever heard of this happening?? Thanks for the help. I'm not very mechanically inclined, only can do basic stuff, and certainly cant drop a tranny or work on the valve body myself. Would def have to pay someone do it.
