Trans Miss Shift

[uh6tdrvr]

My 6 speed has occasionally misshifts from 2-3. So bad that last weekend it nearly thru me into the steering wheel, but it is progressivly getting worse. I took it to the dealer the other day to see if they could duplicate it and couldn't but after explaining it to their trans guy, he is going to replace the pump seal? Its an older TSB but I guess he said he has done it to a vette that had the same issue. Anyone ever heard of this?

[martinzel]

My 6 speed has occasionally misshifts from 2-3. So bad that last weekend it nearly thru me into the steering wheel, but it is progressivly getting worse. I took it to the dealer the other day to see if they could duplicate it and couldn't but after explaining it to their trans guy, he is going to replace the pump seal? Its an older TSB but I guess he said he has done it to a vette that had the same issue. Anyone ever heard of this?

 

 

 

 

 

 

 

 

I believe 2009 6l80s have updated pump sealing rings,they use a rubber expander under the plastic ring,

that is on the pump to the 3-5 clutch drum. pretty sure the pump cover(stator support) is what was changed to use the new rings.

I have a 2010 and mine will 2-3 flare once maybe every 500 miles or so

mine is barely noticiable though ,very light throttle only. Good Luck

[music]

Keep us posted on the outcome. Curious myself. I recall some threads in '09 where folks were complaining about 2/3 shift patterns, and a guy from GM involved with the transmission programming was on here trying to get more info. It seems it related more to a "lag/slip" at slow speeds.

[uh6tdrvr]

Well i was originally told they wanted me to bring it in in the afternoon so that they could start on it the next morning....that was until i dropped it off and ask for a loaner vehicle. Then it changed to it would be ok to bring it to them in the morning. SO they will get it Friday morning. Kind of a bs excuse. I got the "did you buy it here" to "we dont give out loaners" so they will get it friday and if its not done I will drive the loaner that they WILL supply for the weekend. I hate the run around!

[pm26]

Looks like it will be a few more years before GM works out all the bugs wth these transmissions. This is why I like my old proven 4l60E. No issues with that one.

[RyanbabZ71]

Looks like it will be a few more years before GM works out all the bugs wth these transmissions. This is why I like my old proven 4l60E. No issues with that one.

 

[music]

 

Had to laugh... I think there's a bit of truth to "bugs" being worked out, though, since I hear the same kinds of comments on other makes of 6-spd autos. They all use a clutch-to-clutch design, and it's apparently tricky business to get it right under all conditions. Throw in the added "smarts" they're capable of (e.g., predicting how a driver will respond), and it becomes a programming nightmare. It wouldn't stop me from buying one though...

[2005LT]

As robert said, there's definitely a lot of things at play. Mine does this every so often as well. The 2-3 shift will "flare up" as if the clutching mechanism put it into neutral and so with there being no load on the engine temporarily, the RPM jumps...sometimes 200 RPM before it completes the shift and gets the RPM back in line.

 

Usually only happens under some unusual driving condition or circumstance (ie: doing a throttle jab in 2nd and letting off the throttle abruptly right before the shift or something like that).

[uh6tdrvr]

As robert said, there's definitely a lot of things at play. Mine does this every so often as well. The 2-3 shift will "flare up" as if the clutching mechanism put it into neutral and so with there being no load on the engine temporarily, the RPM jumps...sometimes 200 RPM before it completes the shift and gets the RPM back in line.

 

Usually only happens under some unusual driving condition or circumstance (ie: doing a throttle jab in 2nd and letting off the throttle abruptly right before the shift or something like that).

Thats when mine happens and has been getting progressively worse.

As far as bugs, people with 11's getting custom tunes have been reporting that they are pretty well tuned. I would still take my untuned 6 over a 4 speed any day.

[uh6tdrvr]

Update

Got it done today. New pump seal and about 8 qts of Dex6 and its like new. Trans shifts smooth all the way through like it was new...partially because it was reflashed to new but its better now. Fluid looked good and didn't smell burnt nor was it dark. The tech said he didnt see anything that looked out of the norm other than the new seal was thicker. So far so good and i got a near complete fluid swap. Hope this helps if anyone is having miss shifts. Mostly applies to trucks made before Oct 08 in the bulletin.