Hard Trany shifts. Q’s for the pros

[Dirty30]

Hello 1st post here. Came to seek some info on my transmission and ask for advice. My 16 Yukon XL has been shifting hard from 1-2 & 2-1, and sometimes feels like it’s slow to engage and start rolling in 1st, revs a lil and jumps into gear if you don’t give it a sec to engage. Took to dealer & said I needed a whole new trans ($6k) That was almost a year ago. So my question was, if this is a common problem and “just replace this part/that part” or if I need a full replacement or rebuild? Also if so does anyone recommend a certain company or parts to use? I’m thinking I will be buying a new Yukon for family and keeping this for back up or trade this in for the new rig. I’ve had valves replaced and AMF deleted. So with a new tranny do you think it’s smart to keep around or are there other issues know to come up around that 150k mark?
Thank you for any help or insight.

2016 Yukon XL Denali; 128k I have owned since 20k and has been wife’s car and family road trips, no towing, no racing, have replaced trany oil 2-3 times with the last time being the recommended Mobile 1.

 

[donjetman]

Hello 1st post here. Came to seek some info on my transmission and ask for advice. My 16 Yukon XL has been shifting hard from 1-2 & 2-1, and sometimes feels like it’s slow to engage and start rolling in 1st, revs a lil and jumps into gear if you don’t give it a sec to engage. Took to dealer & said I needed a whole new trans ($6k) That was almost a year ago. So my question was, if this is a common problem and “just replace this part/that part” or if I need a full replacement or rebuild? Also if so does anyone recommend a certain company or parts to use? I’m thinking I will be buying a new Yukon for family and keeping this for back up or trade this in for the new rig. I’ve had valves replaced and AMF deleted. So with a new tranny do you think it’s smart to keep around or are there other issues know to come up around that 150k mark?
Thank you for any help or insight.

2016 Yukon XL Denali; 128k I have owned since 20k and has been wife’s car and family road trips, no towing, no racing, have replaced trany oil 2-3 times with the last time being the recommended Mobile 1.

U posted in the 2007-2014 area?

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

@NickTransmissions is our resident transmission expert, and he will chime in with his thoughts and perspective.

 

[blackelky]

If you're anywhere near vegas driving distance just take it to @NickTransmissions he is a gm transmission guru.

 

[NickTransmissions]

Hello 1st post here. Came to seek some info on my transmission and ask for advice. My 16 Yukon XL has been shifting hard from 1-2 & 2-1, and sometimes feels like it’s slow to engage and start rolling in 1st, revs a lil and jumps into gear if you don’t give it a sec to engage. Took to dealer & said I needed a whole new trans ($6k) That was almost a year ago. So my question was, if this is a common problem and “just replace this part/that part” or if I need a full replacement or rebuild? Also if so does anyone recommend a certain company or parts to use? I’m thinking I will be buying a new Yukon for family and keeping this for back up or trade this in for the new rig. I’ve had valves replaced and AMF deleted. So with a new tranny do you think it’s smart to keep around or are there other issues know to come up around that 150k mark?
Thank you for any help or insight.

2016 Yukon XL Denali; 128k I have owned since 20k and has been wife’s car and family road trips, no towing, no racing, have replaced trany oil 2-3 times with the last time being the recommended Mobile 1.

Sounds like either your rear sprag is starting to roll over or 1-2-3-4 piston is cracking...Could also be valve body, pump (worn PR valve), TEHCM and/or torque converter (the TCC is active in gears 2-6 and may not be releasing properly upon the 2-1 downshift).

It will need a full diag work up starting with a test drive w/bi-directional scan tool plugged in to confirm the drivability symptoms as being caused by the trans (Dealer likely already did this, hence their diagnosis) then trans will have to come out, valve body and TEHCM bench tested, TC cut open and trans torn down and inspected.

I can't speak to other, non-transmission related issues other than AFM/DOD, cam bearing and lifter failure are somewhat common for LSX engines north of 175k so if you plan on keeping it for the long haul, I'd do some engine testing/diagnosis to determine if you'll soon need major work there as well before committing to the transmission job.

 

[Dirty30]

U posted in the 2007-2014 area?

Whoops

 

[Fless]

Whoops

No worries. Fixed.

 

[Dirty30]

No worries. Fixed.

Thank you.
Does anyone one know of a company that sells remans with upgraded weak points for these trans? I read that GM replacements don’t address the weak points with their replacements? My Transmission shops near me are very limited so I feel I might try and do it myself as long as I’m not tearing into the insides on the tranny. Replace TC and trans at same time?
Anyone heard of Go-Powertrain? Free shipping and core returns!

 

[NickTransmissions]

Thank you.
Does anyone one know of a company that sells remans with upgraded weak points for these trans? I read that GM replacements don’t address the weak points with their replacements? My Transmission shops near me are very limited so I feel I might try and do it myself as long as I’m not tearing into the insides on the tranny. Replace TC and trans at same time?
Anyone heard of Go-Powertrain? Free shipping and core reruns!

Why are you hesitant to rebuild the transmission?

Per your drivablility symptoms, it's a least 50/50 you'll need to get into the case and overhaul it.

Never heard of Go-powertrain. Post a link to one of their 8L90 remans and ill take a look, give my thoughts.

 

[Dirty30]

Why are you hesitant to rebuild the transmission?

Per your drivablility symptoms, it's a least 50/50 you'll need to get into the case and overhaul it.

Never heard of Go-powertrain. Post a link to one of their 6L80 remans and ill take a look, give my thoughts.

Client Challenge

Reason I’m hesitant, is I guess I’ve never been involved in digging into one and wouldn’t know what I’m looking for. I’ve done a decent amount of backyard mechanic work just nothing with trans.

 

[NickTransmissions]

Client Challenge

Reason I’m hesitant, is I guess I’ve never been involved in digging into one and wouldn’t know what I’m looking for. I’ve done a decent amount of backyard mechanic work just nothing with trans.

Gotcha...At a glance it seems to be priced fairly consistently with what the market is bearing for those units.

 

[Dirty30]

Gotcha...At a glance it seems to be priced fairly consistently with what the market is bearing for instances where the TEHCM is either re-manned or good used so I'd check with them to confirm what TEHCM is being installed (OE new, re-manned or good used) and whether it will be programmed as well as fast-adapted (they dyno test so I imagine it would be but confirm this). One of their line items mentions replacing individual solenoids but this is not possible with a 6L transmission as all are integrated into the TEHCM housing so I'd clarify that as well.

They don't replace bushings unless it shows wear but I replace all bushings with OE GM bushing kits regardless. I'd also request that they install GM's updated HD parking rod assembly, if that's not already part of the deal. Lastly, I'd find out how their warranty works, logistically as well as typical turnaround time.

Awesome info, thank you for that. Do you sell reman tranny’s? Or just work on em?

 

[arkie]

Why are you hesitant to rebuild the transmission?

Per your drivablility symptoms, it's a least 50/50 you'll need to get into the case and overhaul it.

Never heard of Go-powertrain. Post a link to one of their 6L80 remans and ill take a look, give my thoughts.

16 Yukon Denali should be 8 speed

 

[NickTransmissions]

16 Yukon Denali should be 8 speed

Thanks, edited the above. I dont work on the 8-speeds, know very little about them other than their TCs are *****.

 

[Dirty30]

Gotcha...At a glance it seems to be priced fairly consistently with what the market is bearing for those units.

Would it be beneficial to drop pan get a transgo valve body rebuild kit, new wire harness, new temp sensor and see if that helps any? That seems like a fairly easy process I can do one weekend.

 

[NickTransmissions]

Would it be beneficial to drop pan get a transgo valve body rebuild kit, new wire harness, new temp sensor and see if that helps any? That seems like a fairly easy process I can do one weekend.

Sure, no harm in doing so plus you familiarize yourself with the trans. Worst case, it doesn't fix it and you just yank out unit and go through it. Meanwhile, you still have the shift kit in the VB, new harness, etc which can go right back on during overhaul.

 

[duke90]

Just an observation, I was experiencing the same issue with my '17 XL Denali..what felt like a hard downshift from 2-1. Replaced the motor mounts which were completely busted...solved the problem and its been about 10k miles since without issues. Prior to replacing the mounts I took it too the dealer and explained the issue to them...they kept the yukon for a day and then gave me the generic "You'll need to replace the trans" answer.

 

[Bigkevschopshop]

Sure, no harm in doing so plus you familiarize yourself with the trans. Worst case, it doesn't fix it and you just yank out unit and go through it. Meanwhile, you still have the shift kit in the VB, new harness, etc which can go right back on during overhaul.

Great advice, and a new filter with the updated fluid will probably help out alot also. Dont forget to do the Superior cooler bypass while you are down there.

Personally find a good reputable builder if that doesn't fix it. But there are alot of threads on the internet of the harness and VB issue along with GM TSB on the fluid etc. Let us know what you come up with and how things work out.