Could a techm fix my symptoms?

[Gms1987]

Hi Everybody,

I’ve posted this a few years ago as a different question. Symptoms are still the same, but I’d just like to know one thing…. Could replacing the tehcm fix these issues?



My 07 Yukon Denali AWD has 250,000 miles on it. Bought at 204,000 and these symptoms have been around since purchase but haven’t gotten worse.

Tranny was flushed and the fluid and torque converter were replaced at a shop, so I wasn’t able to see the magnet. This all happened in the winter (I live in Pa) at around 235,000 miles. Both symptoms went away for two weeks before returning.



1st Symptom

While driving in the city (no faster than 25 mph) when shifting from 2nd to 1st (windows up or down) the truck feels like someone stabbed the brakes for a split second. Doesn't matter what time of year, day, night, warmed up or cold start... this happens.

2nd Symptom

While driving in the city, if I make a left hand turn off a one-way to a one-way (no stop signs or lights) or a right turn at a stop light, while it's green, when I go to give it gas it revs for a second then I'm moving again. This also happens while going straight and coming to red light that turns green just as I'm within 0-10 feet of coming to a complete stop.

Issue 2 is remedied when I hear a clank and “something” engages.



Could a tehcm replacement fix either of these issues?

Any input is welcome, thank you

 

[donjetman]

Hi Everybody,

I’ve posted this a few years ago as a different question. Symptoms are still the same, but I’d just like to know one thing…. Could replacing the tehcm fix these issues?



My 07 Yukon Denali AWD has 250,000 miles on it. Bought at 204,000 and these symptoms have been around since purchase but haven’t gotten worse.

Tranny was flushed and the fluid and torque converter were replaced at a shop, so I wasn’t able to see the magnet. This all happened in the winter (I live in Pa) at around 235,000 miles. Both symptoms went away for two weeks before returning.



1st Symptom

While driving in the city (no faster than 25 mph) when shifting from 2nd to 1st (windows up or down) the truck feels like someone stabbed the brakes for a split second. Doesn't matter what time of year, day, night, warmed up or cold start... this happens.

2nd Symptom

While driving in the city, if I make a left hand turn off a one-way to a one-way (no stop signs or lights) or a right turn at a stop light, while it's green, when I go to give it gas it revs for a second then I'm moving again. This also happens while going straight and coming to red light that turns green just as I'm within 0-10 feet of coming to a complete stop.

Issue 2 is remedied when I hear a clank and “something” engages.



Could a tehcm replacement fix either of these issues?

Any input is welcome, thank you

@NickTransmissions

 

[NickTransmissions]

Hi Everybody,

I’ve posted this a few years ago as a different question. Symptoms are still the same, but I’d just like to know one thing…. Could replacing the tehcm fix these issues?



My 07 Yukon Denali AWD has 250,000 miles on it. Bought at 204,000 and these symptoms have been around since purchase but haven’t gotten worse.

Tranny was flushed and the fluid and torque converter were replaced at a shop, so I wasn’t able to see the magnet. This all happened in the winter (I live in Pa) at around 235,000 miles. Both symptoms went away for two weeks before returning.



1st Symptom

While driving in the city (no faster than 25 mph) when shifting from 2nd to 1st (windows up or down) the truck feels like someone stabbed the brakes for a split second. Doesn't matter what time of year, day, night, warmed up or cold start... this happens.

2nd Symptom

While driving in the city, if I make a left hand turn off a one-way to a one-way (no stop signs or lights) or a right turn at a stop light, while it's green, when I go to give it gas it revs for a second then I'm moving again. This also happens while going straight and coming to red light that turns green just as I'm within 0-10 feet of coming to a complete stop.

Issue 2 is remedied when I hear a clank and “something” engages.



Could a tehcm replacement fix either of these issues?

Any input is welcome, thank you

Yes, No, Maybe.

How comfortable/confident are you when it comes to working on the transmission, including diagnosis and testing?

You're response to the that question will determine how I answer yours.

 

[Just Fishing]

07, that would have the early style pump stator/seals wouldn't it?
Assuming a it's a 6l80

 

[NickTransmissions]

07, that would have the early style pump stator/seals wouldn't it?
Assuming a it's a 6l80

Yep, early style traditional sealing rings..

I don't want to provide a whole bunch of diag/troubleshooting info, all of which can already be found in my 6L80 Info thread, again if the OP isn't comfortable with getting into his transmission so waiting for him to respond...

 

[Just Fishing]

Yep, early style traditional sealing rings..

I don't want to provide a whole bunch of diag/troubleshooting info, all of which can already be found in my 6L80 Info thread, again if the OP isn't comfortable with getting into his transmission so waiting for him to respond...

The question has my mind running and thinking.
I'm holding back.

 

[Gms1987]

Yes, No, Maybe.

How comfortable/confident are you when it comes to working on the transmission, including diagnosis and testing?

You're response to the that question will determine how I answer yours.

Hey Nick and friends,

I’m 100% comfy/confident working/diagnosing on my transmission.

Some things to keep in mind though:

I’ve never worked on a transmission.

It’s my only vehicle

I’ve watched 6L80 teardowns and nothing stands out as “scary”, but I know I’d need those special snap ring pliers and I really don’t’ want to spend $300ish on a tool I’ll use twice.

With that being said, what did you have in mind?

 

[NickTransmissions]

Hey Nick and friends,

I’m 100% comfy/confident working/diagnosing on my transmission.

Some things to keep in mind though:

I’ve never worked on a transmission.

It’s my only vehicle

I’ve watched 6L80 teardowns and nothing stands out as “scary”, but I know I’d need those special snap ring pliers and I really don’t’ want to spend $300ish on a tool I’ll use twice.

With that being said, what did you have in mind?

That's good to hear...Do a line pressure test first, record pressures at idle in all range settings then while driving, if possible.

Then, while driving, plug in a scan tool with live trans and tcc data showing on the screen. Look at shift speed, tcc slip speed when duty cycle climbs above 50% and see if the tcc slip is more than 10 rpm or so.

If shift speeds are more than 1.5 sec and or tcc slip is > 10 rpm at high duty cycle numbers, drop the pan and observe the bottom. If black clutch material is observed, put the pan back on with a few bolts and yank it for overhaul.

Meanwhile, check out my 6L80 info thread for tear down and reassembly videos. You wont find too many that go into the level of detail that I do with these transmissions.

Let me know if you have more ?s...

 

[Gms1987]

That's good to hear...Do a line pressure test first, record pressures at idle in all range settings then while driving, if possible.

Then, while driving, plug in a scan tool with live trans and tcc data showing on the screen. Look at shift speed, tcc slip speed when duty cycle climbs above 50% and see if the tcc slip is more than 10 rpm or so.

If shift speeds are more than 1.5 sec and or tcc slip is > 10 rpm at high duty cycle numbers, drop the pan and observe the bottom. If black clutch material is observed, put the pan back on with a few bolts and yank it for overhaul.

Meanwhile, check out my 6L80 info thread for tear down and reassembly videos. You wont find too many that go into the level of detail that I do with these transmissions.

Let me know if you have more ?s...

Will do, thank you very much Nick and have a nice evening!

 

[NickTransmissions]

Will do, thank you very much Nick and have a nice evening!

You too, @Gms1987!