Transmission shift solenoid?

[ny_summit]

Recently picked up an 07 denali with 86k miles. Now has 87k. Recently made a post about changing all fluids which I will be soon.

When cruising then giving about moderate throttle to down shift and accelerate it seems to down shift slow, hesitate then seems to "bang" into gear. Doesn't happen everytime. And won't happen when down shifts under light throttle pressure.

All other driving feels smooth and normal. Cruising highway speeds, city speeds exc.

If I shift manually it does not hesitate

Now for the question can it be a shift solenoid? I will soon be dropping the pan to change filter and fluid should I swap out the solenoids while I'm at it? Appreciate any help. Thank you.

 

[Foggy]

I would just drop the pan.. Clean everything you can with brakeclean and put in a
new filter and new fluid.. You might see something in the pan that leads to a
better diagnosis.. If pan looks ok.. I'd do the service and drive for a little bit, it might
just be dirty/old/bad fluid. It wouldn't hurt to add a bottle of LubeGard trans additive..
Get the RED bottle - it's not a 'fix' just a good additive

 

[ny_summit]

I would just drop the pan.. Clean everything you can with brakeclean and put in a
new filter and new fluid.. You might see something in the pan that leads to a
better diagnosis.. If pan looks ok.. I'd do the service and drive for a little bit, it might
just be dirty/old/bad fluid. It wouldn't hurt to add a bottle of LubeGard trans additive..
Get the RED bottle - it's not a 'fix' just a good additive

Will do. Thank you! Is this the product? Also it says to add 1oz per quart of trans fluid. These hold about 12 quarts total correct?

 

[Foggy]

Will do. Thank you! Is this the product? Also it says to add 1oz per quart of trans fluid. These hold about 12 quarts total correct?

That's the stuff.. Just add one full bottle at each service. I've been using this on many many cars for many years. It's the only stuff my old school trans guys like.. (they do make some alternative
ones app specific, but the red bottle is the right one 90% of the time)

 

[NickTransmissions]

Will do. Thank you! Is this the product? Also it says to add 1oz per quart of trans fluid. These hold about 12 quarts total correct?

Any DTCs? If unsure, id put a scanner on it to see if anything is stored. Sometimes trans/chassis/abs codes will store but not generate a CEL…

At 87k, assuming the transmission’s electronics haven’t been replaced already, id replace them all with genuine GM/AC Delco/Borg Warner solenoids (epc, shift solenoids A, B, 3-2 control solenoid and PWM solenoid as well as pressure switch manifold assembly and wiring harness) so you don’t have to go back underneath again until its time to pull the trans for overhaul.

Also check your band clearance by moving the band back and forth on the drum (reach up beyond the parking rod to put your fingers on the band). It should move back/forth by no more than 1/8” of an inch.

If you have appreciably more travel than 1/8”, you can shim the servo using a golden ring spacer from Transgos SK4L60E shift kit.

New filter and gasket and whichever trans fluid you prefer as long as it meets latest requirements.

 

[swathdiver]

Any DTCs? If unsure, id put a scanner on it to see if anything is stored. Sometimes trans/chassis/abs codes will store but not generate a CEL…

At 87k, assuming the transmission’s electronics haven’t been replaced already, id replace them all with genuine GM/AC Delco/Borg Warner solenoids (epc, shift solenoids A, B, 3-2 control solenoid and PWM solenoid as well as pressure switch manifold assembly and wiring harness) so you don’t have to go back underneath again until its time to pull the trans for overhaul.

Also check your band clearance by moving the band back and forth on the drum (reach up beyond the parking rod to put your fingers on the band). It should move back/forth by no more than 1/8” of an inch.

If you have appreciably more travel than 1/8”, you can shim the servo using a golden ring spacer from Transgos SK4L60E shift kit.

New filter and gasket and whichever trans fluid you prefer as long as it meets latest requirements.

Hey Nick, the guy asking the questions has a 6L80. He's probably referring to replacing the little clear discs in the TECHM.

6L80 Sonnax ZIP Kit, Pressure Switch rebuild, remote filter install, and fluid flush in 2013 Escalade ESV (Pic heavy)

Hello Gentlemen, Over the past few days, I have completed the following work to the 6L80 transmission in my 2013 Escalade ESV: -rebuilt the TECHM pressure switches using Sonnax parts -installed most of the Sonnax ZIP kit in the valve body -replaced the filter -installed a new pan with a drain...

www.tahoeyukonforum.com

 

[NickTransmissions]

Hey Nick, the guy asking the questions has a 6L80. He's probably referring to replacing the little clear discs in the TECHM.

6L80 Sonnax ZIP Kit, Pressure Switch rebuild, remote filter install, and fluid flush in 2013 Escalade ESV (Pic heavy)

Hello Gentlemen, Over the past few days, I have completed the following work to the 6L80 transmission in my 2013 Escalade ESV: -rebuilt the TECHM pressure switches using Sonnax parts -installed most of the Sonnax ZIP kit in the valve body -replaced the filter -installed a new pan with a drain...

www.tahoeyukonforum.com

The OP mentions picking up a 2007 Yukon Denali so I figure he has a 4L65 (M32) or 4L70 (M70) 2007 was a transition year for those trans and the higher end SUVs came with either the 65 or 70, IIRC.

 

[donjetman]

They came w/6L80e, like mine.
rpo=MYC

 

[Geotrash]

They came w/6L80e, like mine.
rpo=MYC

Yup '07 Denali's (6.2L) had the 6L80. The regular Yukons had the 4L.

 

[NickTransmissions]

Yep, forgot the vehicles that came w/the 6.2L L92 engines got the 6L80s, thanks for catching...The harsh downshifting can be possibly attributed to the TECHM and a relearn/reflash should fix it, assuming that's the problem. It could also be wear in the valve / solenoid body casting. Id check fluid to see if any burnt smell is present if that hasn't been done already. @ny_summit does this issue happen at all speeds across multiple gears or just highway speeds while in OD w/converter in lock up?