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Discussion Starter #1
GM’s 8L45 Eight-Speed Cadillac CT6 Automatic Transmission: Recall, Replace, Re-tune or Deny

GM’s 8L45 Eight Automatic Transmission is a clunker. GM’s customer assistance center acknowledges that the reviews are ‘mixed’ and one service bulletin has been issued. The ‘mixed’ aspect of the feedback shows that this 8L45 works normally for a while for some owners. Internet forums are heating up with discussions about otherwise fine cars cursed with this crude, confused and embarrassingly bad 8 speed lemon.

General Motors has managed to take its customers back several decades to an unpleasant time in the early development of the automatic transmission. The GM 8L45 Hydramatic Transmission is part of the powertrain in the Cadillac CT6, CTS, ATS, Chevrolet Camaro and perhaps more vehicles under a different name. This questionable feat of backwards design and engineering was accomplished with variable force solenoid technology, speed sensors and a processor executing hundreds of calculations and commands every 6.25 milliseconds. Clearly, this is not often enough, as evidenced by the ride experience inflicted on the driver and passengers when the thing desperately hunts for the proper gear and any gear will do … to lurch forward. With all that technology it performs far worse than the bands and torque converters of that our grandparents enjoyed in the 1960’s and later. In 2016, General Motors was simply not ready to evolve past the 6 speed transmission but that didn’t stop it from going ahead and cursing entire fleets of its new vehicles with the crudest powertrain component in its history. And yes indeed, it weighs over 30 lbs. less than its predecessor (one that actually works, though evidently grossly overweight). Perhaps the elusive 2nd, 3rd and 4th gears each weigh 10 lbs., accounting for both the weight loss and crude performance.

The 8L45 is a mess. Its crude state of performance sometimes rears its ugly head on a new GM vehicle on its way home from the dealership, or lurks deep inside its innards for a later outbreak of hard shifts, flares, thunks, and head jerking downshifts at random times in the early lives of the fleet. GM’s confidence with this clunker drove it to install it in the Cadillac CT6, CTS and ATS models. Dealerships are forced to appease customers with such phrases as ‘performs as designed’ and ‘performed adaptive fast learn’ as a way to force owners to get used to it. The other line of defense is that the transmission is learning and adapting to the driver’s style. Enduring the explanations and excuses of GM service technicians and service managers can be tiring. Confidentially, they’ll admit that the thing is a disaster.

Other than a single service bulletin, GM is ignoring this failure as of Spring 2017. To admit there’s a problem would be a devastating blow to the marketability of its current unsold inventory. There is also a lot of ego at stake here. GM promoted the 8L45 in its literature in a series of puffed up articles with statements like this:

“The 8L45 was designed to enhance the CT6’s driving experience, offering a strong balance between performance and efficiency,” said Bill Goodrich, GM’s assistant chief engineer for eight-speed automatic transmissions “Perhaps its best attribute will be that customers really won’t notice it – they’ll simply enjoy the CT6’s seamless, smooth driving experience and on-demand performance.”

Read more: http://gmauthority.com/blog/2015/03/new-8l45-eight-speed-automatic-to-debut-in-2016-ct6/#ixzz4k4cZAecM

The owner of a vehicle cursed with this clunker will know there’s a problem when passengers ask why the brakes are being pumped when coasting to a stop. That’s the 8L45’s attempt at downshifting. When the driver gingerly feathers the accelerator to coax the thing into gear after an auto-stop shutdown it may skip several gears and slam into 4th or 5th with a violent shutter. The driver and passengers all feel it as the entire vehicle shutters. At times it may seem like the driveshaft is going to come up through the cupholder and cellphone battery charger. Its performance is indefensible. If it’s shifting like an average GM vehicle and it hasn’t yet slipped into this confused state, it soon will. No amount of learning, adaptive fast learns or software tunes can apparently help it find the right gears, other than reverse or park, which, luckily seem to work. Dealer lots are filling up with unsold inventory and returned vehicles, many with less than 2000 troubled miles on the odometer. Apparently, frustrated owners were not able to adapt and learn along with the car’s stuttering, clunking, and confused transmission.
So, what is the future of the 8L45? Maybe a software tune can bring it under control. If this is not possible, and clearly, GM is in no hurry to resolve this issue, the fate of the 8L45 has these possible futures:

1. It will quietly disappear in 2018, leaving the current fleet in an abyss of wildly unpopular clunkers. The CT6 is becoming known as the shimmying, stuttering, lurching flagship that looks nice.

2. It can finally break in at 40,000 miles or so and can then find the correct gears at appropriate times after a few years of learning and adapting.

3. Third party after-market companies will offer a way to replace and retrofit it with a nicely functioning transmission, like the 6L45, thus salvaging the resale value of the CT6 and others.


Corporate denial doesn’t help the brand. Blaming the customer for expecting better shifting insults the brand loyalists. It’s clear that the 8L45 was rushed into production without quality engineering and design. Hopefully, GM and its Cadillac division can conjure up a solution that can make its attractive CT6 flagship drive as nicely as it looks parked.
 

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'16 CTS V-Sport Black/'16 CTS Luxury w/V-Sport Pkg White
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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

NICELY WRITTEN!!!!

for a piece of fiction

my 8L45 has been working great for 13,789 miles so far
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

It’s clear that the 8L45 was rushed into production without quality engineering and design.


My 2014 CTS is equipped with the 8 speed Aisin transmission which was used before GM developed their own. It is a wonderfully smooth shiftng and responsive transmission.
 

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2016 CT6 AWD 3.6
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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

I think my CTS transmission is pretty decent. The main complaint I have so far is the 1-2 shift and that does seem to perform well on some occasions, but not all. I like the smooth shifts in all other gears and especially that the transmission does a good job at moving the vehicle quickly from a stop. I sometimes feel that the car is lugging in too low a gear for my liking. I noted that 8 speed automatics are fairly new over at Lexus too, and their forums also have complaints about those transmissions too, especially wrt rx350 transmissions. That said, it doesn't excuse Cadillac for not addressing this issue properly. GM has enough $ to fix these problems through a formal recall or some other process.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

I would like to know the "source" of that diatribe; the link to the gmauthority mentions none of that.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

I would like to know the "source" of that diatribe; the link to the gmauthority mentions none of that.
the daily troll, the troll journal, the washington troll....pick your source
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

The 8L90 is not any better. My 8L90 in my CT6 with turbo 3.0 is terrible. Worst transmission I have ever had. The 1-2 shift is hard. It also depends on outside temperature whether it acts up to a greater extent. I think the 8L90 could use better fluid or better pressure sensors. You guys that claim to have a good transmission should be thankful and don't dispel the ones that don't like they are trolls.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

My '14 VSport had an Aisin unit and my '17 has the same one. They are wonderful transmissions. I drove both a TT CT6 and 2.0T ATS and both trannies were very smooth. I also have read numerous articles about the V6 Camaro with the same tranny. They are all very positive. Sorry you're experiencing troubles.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

The 8L90 is not any better. My 8L90 in my CT6 with turbo 3.0 is terrible. Worst transmission I have ever had. The 1-2 shift is hard. It also depends on outside temperature whether it acts up to a greater extent. I think the 8L90 could use better fluid or better pressure sensors. You guys that claim to have a good transmission should be thankful and don't dispel the ones that don't like they are trolls.
I was having some of the problems mentioned on mine also, but lately it has been acting much better to the point I don't think I will mention it at my next service. When cold it used to clunk on the 1-2 shift and when coming to a stop it would clunk just before the stop in the 3-1 shift. Now, all of the low gear shift problems are completely gone; it just took 4 months to learn.

The one thing I did, and it may be purely coincidental, was to make a few high power accelerations onto the freeway over a couple of days. After that it seemed to change the way it shifted.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

The 8L90 is not any better. My 8L90 in my CT6 with turbo 3.0 is terrible. Worst transmission I have ever had. The 1-2 shift is hard. It also depends on outside temperature whether it acts up to a greater extent. I think the 8L90 could use better fluid or better pressure sensors. You guys that claim to have a good transmission should be thankful and don't dispel the ones that don't like they are trolls.
OP is trolling .....I recognise folks have problems with cars from time to time and i feel for those folks......OPs proclamation, however, that they are all bad and hellfire is raining down from the heavens is too far.....8L45 is a low torque version of 8L90 which is used for high torque applications and both have simply been sold on WAY too many cars in the past 3 years with positive reviews for OPs proclamations to be true...

my own personal experience with my wife's car having the 8L45 doesn't line up with OPs statements, to which you state i should be thankful. However my professional experience doesn't line up with OPs experiences either.

what i mean by this is i'm in charge of our 50 car fleet of loaners (no transmission issues) and the $25 million in inventory of which 180 are here or have been sold in the last 6 months equipped with this transmission, and i don't hear from our service department regarding this. I also do not hear anything bad from my loaner customers regarding this nor have i experienced any issues when i drive them. there is nothing to dispel, and far too many cars to consider my personal good fortune luck.

my personal view is a lot of folks aren't used to how these transmissions feel, and operate...these transmissions are hyper efficient, compared to the past and have 4 clutches in them locking gears together in order to gain that efficiency, it's again my opinion the feel of these clockworks is new and foreign so some might complain...to extend my theory i suspect the transmission may be tight and possibly a bit less refined at first until it is broken in, improving with use which in my view is much better than one that starts good and can only deteriorate from there
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

First off this is probably my first post here so thanks for a great site. I am in a good number of car forums but don't post unless I have knowledge/first hand experience.

I have 2017 CT6 with 3.0TT. 16,000 miles - picked up in February. Love Cadis - last one a STSV - had lots of off the floor upper end cars - built hot rods. I read about tranny and problems on this forum. I test drove one and felt the problems. I knew for sure as and American made Cadillac they would have a fix. Mine is in the shop AGAIN today. I am not the only one. It is a shame. If they actually have a fix and don't tell me that they reflashed it, or it needs to learn I will let you know.

Tired of spilled coffee on my shirt
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

I was having some of the problems mentioned on mine also, but lately it has been acting much better to the point I don't think I will mention it at my next service. When cold it used to clunk on the 1-2 shift and when coming to a stop it would clunk just before the stop in the 3-1 shift. Now, all of the low gear shift problems are completely gone; it just took 4 months to learn.

The one thing I did, and it may be purely coincidental, was to make a few high power accelerations onto the freeway over a couple of days. After that it seemed to change the way it shifted.
Yes I noticed the same thing. Things improved a lot after a long distance trip with several spirited accelerations.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

OP is trolling .....I recognise folks have problems with cars from time to time and i feel for those folks......OPs proclamation, however, that they are all bad and hellfire is raining down from the heavens is too far.....8L45 is a low torque version of 8L90 which is used for high torque applications and both have simply been sold on WAY too many cars in the past 3 years with positive reviews for OPs proclamations to be true...

my own personal experience with my wife's car having the 8L45 doesn't line up with OPs statements, to which you state i should be thankful. However my professional experience doesn't line up with OPs experiences either.

what i mean by this is i'm in charge of our 50 car fleet of loaners (no transmission issues) and the $25 million in inventory of which 180 are here or have been sold in the last 6 months equipped with this transmission, and i don't hear from our service department regarding this. I also do not hear anything bad from my loaner customers regarding this nor have i experienced any issues when i drive them. there is nothing to dispel, and far too many cars to consider my personal good fortune luck.

my personal view is a lot of folks aren't used to how these transmissions feel, and operate...these transmissions are hyper efficient, compared to the past and have 4 clutches in them locking gears together in order to gain that efficiency, it's again my opinion the feel of these clockworks is new and foreign so some might complain...to extend my theory i suspect the transmission may be tight and possibly a bit less refined at first until it is broken in, improving with use which in my view is much better than one that starts good and can only deteriorate from there
So the fleet have the 8L45, any with the 8L90? Any other non transmission issues? I find my CTS be otherwise very good build quality...I think it will hold up well.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

So the fleet have the 8L45, any with the 8L90? Any other non transmission issues? I find my CTS be otherwise very good build quality...I think it will hold up well.
all my loaners currently with 8L45 are ATS and CTS which is about a dozen but of the rest of my 400 cars about 90 have 8L45 (ATS/CTS/CT6) & 8L90 (ATS-V/CTS-V/Escalade/Escalade ESV/Yukon/Yukon XL/Sierra)
 

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Discussion Starter #15
Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

To be clear, my article is not about those barely perceptible quivers and shift sequences experienced with most of the 8 speed transmissions in the market. What I am addressing are the violent shifts, head lurching downshifts and abysmal performance of GM’s 8L45 transmission that is the curse of the Cadillac CT6.

The perspective formed, as presented in my post is based on two 8L45’s, one exhibiting all of its faults on the day of delivery and the second one performing relatively normally until mile number 2435, when all hell broke loose. Again, this pertains to the 8L45 in two Cadillac CT6’s that I have owned. Additionally, an internet search of other GM discussion forums brings up similar complaints wherever the same transmission is part of the powertrain. Following through with Cadillac customer support and GM corporate discussions it’s clear that the customer base is not universally pleased with this crude transmission. As one would expect, the people in these two GM areas are very polite, helpful and proactive and admit there are concerns. It’s not about customers who not quite ready for fuel saving technology that needs to shift constantly. My issue with GM is its slowness in dealing with the CT6’s problems and the pompous pre-sale promotion of a transmission that ‘makes the driver unaware that it’s shifting.’ Believe me, when your CT6 issues loud thunks, can barely get through a busy intersection after an auto start/stop lurch as it searches for a gear, you’ll want to get rid of the thing. The CT6, with its eye-catching edgy design, can be an extremely unpleasant car to drive when its transmission can’t shift correctly, in a violent fashion.

The notion that these things are highly sophisticated and require a long break-in period is silly. Some arrive from the factory in a confused state while others don’t lapse into their failure mode until much later. And again, it’s not about those common 8 speed transmissions’ slight quivers and shakes. Apparently 8, 9 and 10 speed transmission technology is driven by fuel economy and acceptable performance from a piddly little 4 or 6 cylinder engine. I realize that the current fleet of Cadillacs are budget luxury cars and expectations have to be adjusted to these price points, but can you imagine telling this to customers in the real luxury car market? 'Get used to it! or You're not driving it right', 'Performs as designed' or 'You're expecting too much' and other arguments would not set well with affluent owners.

Regarding the level of dialogue found here, most of the enthusiasts’ discussion here are helpful, insightful and productive. However, as in any forum of anonymous posters with silly nicknames, it only takes one or two to drag us all back to seventh grade. While sometimes amusing, it’s best to put those posters on ‘ignore’ and their insults do not appear in the thread. That’s the best way to put seventh grade behind and focus on the discussion of common concerns, solutions, perspectives, ideas and questions, among adults who actually own these otherwise fine CT6's.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

as always the aggrieved, scream the most and are the most proactive in getting their complaints heard. As i've said before, things go bad, these are human made mechanical things after all, and i have empathy for those that were let down by their cars, but OP (who seems to have been unlucky twice) is drawing with too broad of strokes and obviously has (and is entitled to) his opinions. I would say to this, that researching in forums will lead you down silly paths, because all you would have accomplished is to find others aggrieved like you and not gain a clear overall picture of the good cars relative to the bad ones.

first it was the 8L45 that was the villain, all of them regardless of brand or model based on the title OP chose for this thread, and now OP has narrowed his ire to 8L45 in CT6s, but again I would argue this is too broad...The CT6 is not and was not meant to be a volume seller, we sell about 2 a month, and every single one of our customers is happy with them....Only one had a bad time, and that was our very first CT6 (a special order 4 cylinder RWD with the 8L45) which had an unfixable leaky sunroof. We tried to fix it, got GM to send engineers to try and fix it, and GM ultimately took the car back and we ordered a new car for the customer, and not only is he happy with the car, he's happy with how he was taken care of by GM....on average Cadillac sells over 1000 of these a month (1044 monthly average over the past 12 months to be exact) there is no way OP's experience applies to 12 thousand cars. That would be a juicy Takata Airbag kind of news story that would make national airways

Alas, to use OPs words "However, as in any forum of anonymous posters" i believe OP to be typical of the screaming minority that can be found in just about every car forum about a plethora of grievances
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

Driving around today, I would say the 1-2 shift is not worthy of a Cadillac. I've driven a CT6 demo with 5k km and it was similar but at least seemed to have less of a lurch. Cadillac should have figured this out before launching these transmissions in Cadillacs. This is one of the things that bother me about my CTS. If it gets worse like OP claims I would definitely take it in. Luckily it seems t have improved or I've adjusted my driving style to compensate. Other than that, these cars are amazing and the smoothness of the powertrain is great. I think both interior and exterior finish of these cars is excellent.
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

Picked mine back up today. 3 full days testing and yep - they reflashed it again. Said drive for 200 miles and it ought to be great - just like before. It did seem better as it always does, but we will see if it lasts. I have swamp land in Florida if anyone needs any. My wife keeps asking me why I bought it - I keep saying the same thing - I can't believe Cadi can't fix it or make it right.

I will wear a dark shirt and pants so the coffee stains aren't so easy to see.

Bruce
 

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Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

as always the aggrieved, scream the most and are the most proactive in getting their complaints heard. As i've said before, things go bad, these are human made mechanical things after all, and i have empathy for those that were let down by their cars, but OP (who seems to have been unlucky twice) is drawing with too broad of strokes and obviously has (and is entitled to) his opinions. I would say to this, that researching in forums will lead you down silly paths, because all you would have accomplished is to find others aggrieved like you and not gain a clear overall picture of the good cars relative to the bad ones.

first it was the 8L45 that was the villain, all of them regardless of brand or model based on the title OP chose for this thread, and now OP has narrowed his ire to 8L45 in CT6s, but again I would argue this is too broad...The CT6 is not and was not meant to be a volume seller, we sell about 2 a month, and every single one of our customers is happy with them....Only one had a bad time, and that was our very first CT6 (a special order 4 cylinder RWD with the 8L45) which had an unfixable leaky sunroof. We tried to fix it, got GM to send engineers to try and fix it, and GM ultimately took the car back and we ordered a new car for the customer, and not only is he happy with the car, he's happy with how he was taken care of by GM....on average Cadillac sells over 1000 of these a month (1044 monthly average over the past 12 months to be exact) there is no way OP's experience applies to 12 thousand cars. That would be a juicy Takata Airbag kind of news story that would make national airways

Alas, to use OPs words "However, as in any forum of anonymous posters" i believe OP to be typical of the screaming minority that can be found in just about every car forum about a plethora of grievances

The bolded in the second paragraph is mine.

Your dealership stepped up and made a customer very satisfied with you and GM. That's what we all wish for when an issue cannot be resolved. I've been fortunate enough to find an excellent dealer with phenomenal customer service. The service department spoiled me for anyone else.

From a customer's standpoint this is the most important part of the car purchasing and ownership experience. We expect things to go well when buying a new car. Occasionally that doesn't happen. The dealer who responds well has our business, loyalty and positive word of mouth forever.

I've become evangelical about my servicing dealer. Friends are tired of hearing about it but it doesn't stop me :)
 

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Discussion Starter #20
Re: GM’s 8L45 Cadillac Automatic Transmission: Recall, Replace, Re-tune or Deny

Picked mine back up today. 3 full days testing and yep - they reflashed it again. Said drive for 200 miles and it ought to be great - just like before. It did seem better as it always does, but we will see if it lasts. I have swamp land in Florida if anyone needs any. My wife keeps asking me why I bought it - I keep saying the same thing - I can't believe Cadi can't fix it or make it right.

I will wear a dark shirt and pants so the coffee stains aren't so easy to see.

Bruce
rblong333 Bruce,
By 'reflashing' are the service techs writing 'Relearned all shift adapts and performed fast learn procedure'?

Based on conversations with personnel at one of the northeast's largest dealerships, along with my smaller dealership, that's about all they can do to get these things back under control, though they warn that it doesn't really last. I have yet to encounter a service technician, around here anyway, that defends this thing. Corporate doesn't offer much encouragement either, but we're working on it. Sorry about spilling your coffee and the rough ride.... not much fun.
 
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