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Posted
On 1/26/2022 at 7:33 AM, voided3 said:

Yes, driving in L7 on the 8-speed turns off DFM and prevents the transmission from shifting into 8th gear. Both this method and the the Pulsar or Range DFM disabler are software means of disabling it. It is believed that disabling the system reduces the likelihood of lifter failure as the lock pins in the lifters are not being cycled on and off constantly. They instead just stay in the fully extended position like a normal lifter.

 

The best way to delete DFM is with essentially a new valvetrain as I described (non-DFM lifters, different pushrods, different cam, ECU tune, etc.). I'm not sure if these aftermarket parts even exist yet for the current L84 5.3 or L87 6.2 V8s, though, as the majority are still under warranty and the newer GM ECUs sound like they are harder to re-tune.


Sorry for the slow response. Covid issues. I guess I’m going to check out the Pulsar and Range and definitely not baby this truck. Either get some confidence or let it be someone else’s problem. Based on this conversation I have no idea what else is worth owning. I’ve been driving in L7 and will continue to research. Someone mentioned a DFM delete that also deletes auto stop. That’s worth looking in to. Your other option sounds like it might work but is extreme to the point where I would buy something different first. Thanks. 

Posted
12 hours ago, SilverMak said:


Sorry for the slow response. Covid issues. I guess I’m going to check out the Pulsar and Range and definitely not baby this truck. Either get some confidence or let it be someone else’s problem. Based on this conversation I have no idea what else is worth owning. I’ve been driving in L7 and will continue to research. Someone mentioned a DFM delete that also deletes auto stop. That’s worth looking in to. Your other option sounds like it might work but is extreme to the point where I would buy something different first. Thanks. 

Yeah, it's a tough situation. The whole point of buying a new vehicle is so you have reliable transportation, but the ownership experience for ours has been more akin to owning a 15 year old vehicle from a reliability standpoint. It spent nearly two months at the dealership in the first year of ownership. Every time I start the truck, I say to myself "Hey, it actually started!" and when I get back home I say "Hey, it didn't blow up this time!"

 

Emotional ranting aside, yes, we're definitely going to be getting rid of it before 5 years/60,000 miles, potentially as early as one/two years from now. We may have to sacrifice some practicality and step up to a gas 3/4 ton to get something that can last longer than five years, it seems.

 

On a somewhat positive side note, driving in L7 also disables auto start/stop, so it's a convenient one-stop-shop. I still disable it with the switch every time reflexively, anyway.

Posted
On 2/7/2022 at 8:09 AM, voided3 said:

Yeah, it's a tough situation. The whole point of buying a new vehicle is so you have reliable transportation, but the ownership experience for ours has been more akin to owning a 15 year old vehicle from a reliability standpoint. It spent nearly two months at the dealership in the first year of ownership. Every time I start the truck, I say to myself "Hey, it actually started!" and when I get back home I say "Hey, it didn't blow up this time!"

 

Emotional ranting aside, yes, we're definitely going to be getting rid of it before 5 years/60,000 miles, potentially as early as one/two years from now. We may have to sacrifice some practicality and step up to a gas 3/4 ton to get something that can last longer than five years, it seems.

 

On a somewhat positive side note, driving in L7 also disables auto start/stop, so it's a convenient one-stop-shop. I still disable it with the switch every time reflexively, anyway.


I’m not making any long term decisions yet but my experience hasn’t been nearly as bad as yours. Interesting that you mentioned L7 disabling auto stop. I hadn’t even noticed that. I guess the only time I notice auto stop is when it actually happens. 
 

With the 3/4 ton, are you talking about the 6.6 engine to avoid this problem?

Posted
10 hours ago, SilverMak said:


I’m not making any long term decisions yet but my experience hasn’t been nearly as bad as yours. Interesting that you mentioned L7 disabling auto stop. I hadn’t even noticed that. I guess the only time I notice auto stop is when it actually happens. 
 

With the 3/4 ton, are you talking about the 6.6 engine to avoid this problem?

Yes, though since the GM 6.6 L8T is still GDI just like the L84 5.3, I'm leaning more towards a Ford F250 with the older 6.2 gas V8 since it also has a port injector(s) to keep the intake valves clean. I'm ruling out Ram's 6.4 Hemi in their 3/4 ton because it still has cylinder deactivation just like the 1/2 tons.

Posted

Saw this thread and figured I would add to it with what MIGHT be a relevant post.  Had my ‘21 Sierra 1500 Elevation towed to my dealer after it basically just “failed” while routinely driving this past weekend.  They have had it since Monday, gave no updates/diagnosis and just today mentioned LIFTERS as a possible culprit. 
 I had several dash lights/icons (parking brake, engine, parking assist, and SERVICE ESC) illuminate while the truck made a clicking noise and sounded very labored and heavy….I pulled over, shut it off, etc…..and finally called my dealer service center….they said to drive it the final 5 miles to my home and call GMC Roadside Assistance……which brings me to today and the mentioning of “lifters”…..I’ll continue to monitor this site and this thread for further info/ideas/experiences/etc. 

Thanks to all for sharing your thoughts.

 

Posted
2 hours ago, SigPig94 said:

Saw this thread and figured I would add to it with what MIGHT be a relevant post.  Had my ‘21 Sierra 1500 Elevation towed to my dealer after it basically just “failed” while routinely driving this past weekend.  They have had it since Monday, gave no updates/diagnosis and just today mentioned LIFTERS as a possible culprit. 
 I had several dash lights/icons (parking brake, engine, parking assist, and SERVICE ESC) illuminate while the truck made a clicking noise and sounded very labored and heavy….I pulled over, shut it off, etc…..and finally called my dealer service center….they said to drive it the final 5 miles to my home and call GMC Roadside Assistance……which brings me to today and the mentioning of “lifters”…..I’ll continue to monitor this site and this thread for further info/ideas/experiences/etc. 

Thanks to all for sharing your thoughts.

 

 

Am I misreading your post?  Did you say they have had since Monday and today "mentioned" lifters as a possible culprit?  I mean, it should take a qualified tech about 20 mins to fully diagnose a collapsed DFM lifter.

Posted
1 hour ago, Kilgore Trout said:

 

Am I misreading your post?  Did you say they have had since Monday and today "mentioned" lifters as a possible culprit?  I mean, it should take a qualified tech about 20 mins to fully diagnose a collapsed DFM lifter.

Nope, not misreading…….I’m willing to believe that Covid has caused delays in many areas such as staffing…..and the manager said they are operating with a skeleton staff in the service dept……but I’d be lying if I said I wasn’t surprised when I heard nothing regarding a diagnosis for 2 full days.  

Posted
13 hours ago, voided3 said:

Yes, though since the GM 6.6 L8T is still GDI just like the L84 5.3, I'm leaning more towards a Ford F250 with the older 6.2 gas V8 since it also has a port injector(s) to keep the intake valves clean. I'm ruling out Ram's 6.4 Hemi in their 3/4 ton because it still has cylinder deactivation just like the 1/2 tons.


i guess the research never ends. Thought I was done besides looking at modifications when I bought this truck. 

Posted
3 hours ago, SigPig94 said:

Saw this thread and figured I would add to it with what MIGHT be a relevant post.  Had my ‘21 Sierra 1500 Elevation towed to my dealer after it basically just “failed” while routinely driving this past weekend.  They have had it since Monday, gave no updates/diagnosis and just today mentioned LIFTERS as a possible culprit. 
 I had several dash lights/icons (parking brake, engine, parking assist, and SERVICE ESC) illuminate while the truck made a clicking noise and sounded very labored and heavy….I pulled over, shut it off, etc…..and finally called my dealer service center….they said to drive it the final 5 miles to my home and call GMC Roadside Assistance……which brings me to today and the mentioning of “lifters”…..I’ll continue to monitor this site and this thread for further info/ideas/experiences/etc. 

Thanks to all for sharing your thoughts.

 


That sounds almost exactly like my experience when the failure occurred. The dash lit up with multiple errors including traction control. I’m surprised you were able to drive 5 miles to get home. Mine sounded so bad I just pulled over at the first lighted area and paid for a tow to the nearest dealership, not where I purchased the truck. This was at 8 at night and they called me before 8 the next morning with the verdict. How many miles are on your truck? When did you buy it? There is at least one GM bulletin on what they’ll do in this situation but it depends on how many miles you’ve put on the truck. Mine is running fine since this happened but I’m really low mileage. For me, they replaced all 16 and determined no other damage. 

Posted
12 hours ago, SilverMak said:


That sounds almost exactly like my experience when the failure occurred. The dash lit up with multiple errors including traction control. I’m surprised you were able to drive 5 miles to get home. Mine sounded so bad I just pulled over at the first lighted area and paid for a tow to the nearest dealership, not where I purchased the truck. This was at 8 at night and they called me before 8 the next morning with the verdict. How many miles are on your truck? When did you buy it? There is at least one GM bulletin on what they’ll do in this situation but it depends on how many miles you’ve put on the truck. Mine is running fine since this happened but I’m really low mileage. For me, they replaced all 16 and determined no other damage. 

Thanks for your reply…..I have almost 14k miles on it and I’ve read about how the mileage dictates what gets done…..meaning how many lifters are repaired/replaced.  I specifically asked the dealer service department if I could drive it home and if I would be damaging anything if I did so.  They told me to get it home and call Roadside Assistance.  Looks like I’m now just in a wait cycle… no loaners so I rented a car on my own, no idea how readily available parts are, no idea when this repair will be complete…… I’m just trying to stay patient and upbeat…no sense pissing and moaning.

 

 

 

 

Posted
3 hours ago, SigPig94 said:

Thanks for your reply…..I have almost 14k miles on it and I’ve read about how the mileage dictates what gets done…..meaning how many lifters are repaired/replaced.  I specifically asked the dealer service department if I could drive it home and if I would be damaging anything if I did so.  They told me to get it home and call Roadside Assistance.  Looks like I’m now just in a wait cycle… no loaners so I rented a car on my own, no idea how readily available parts are, no idea when this repair will be complete…… I’m just trying to stay patient and upbeat…no sense pissing and moaning.

 

 

 

 

Rented a car on your own?  That rental should be covered by the dealership.  At least mine is covering that cost.

 

Posted (edited)
5 hours ago, SigPig94 said:

Thanks for your reply…..I have almost 14k miles on it and I’ve read about how the mileage dictates what gets done…..meaning how many lifters are repaired/replaced.  I specifically asked the dealer service department if I could drive it home and if I would be damaging anything if I did so.  They told me to get it home and call Roadside Assistance.  Looks like I’m now just in a wait cycle… no loaners so I rented a car on my own, no idea how readily available parts are, no idea when this repair will be complete…… I’m just trying to stay patient and upbeat…no sense pissing and moaning.

 

 

 

 

You need to be raising hell that they pay for your rental at least. I would reach out to the executive email and get back what you have paid.  At minimum. 

Edited by 1454
Posted
18 hours ago, 1454 said:

You need to be raising hell that they pay for your rental at least. I would reach out to the executive email and get back what you have paid.  At minimum. 

One new bank of lifters “should be in this morning” and will be installed….they apparently need two days to complete.  I inquired about how to file for rental reimbursement, so I’ll see where that goes when/if someone gets back to me.  As I stated in my earlier post, I am willing to accept delays because of Covid, short-staffing, etc…..I am trying to NOT raise hell because I know these are crazy times and i feel the calm approach will get me my truck back faster than yelling at someone (as much as I’d like to)…..although if I am to believe all the reports that dealerships have no inventory, shouldn’t the Sales department be operating with a skeleton staff and NOT Service?!  Whatever…..the dance continues…….

  • Like 1
Posted
7 minutes ago, SigPig94 said:

One new bank of lifters “should be in this morning” and will be installed….they apparently need two days to complete.  I inquired about how to file for rental reimbursement, so I’ll see where that goes when/if someone gets back to me.  As I stated in my earlier post, I am willing to accept delays because of Covid, short-staffing, etc…..I am trying to NOT raise hell because I know these are crazy times and i feel the calm approach will get me my truck back faster than yelling at someone (as much as I’d like to)…..although if I am to believe all the reports that dealerships have no inventory, shouldn’t the Sales department be operating with a skeleton staff and NOT Service?!  Whatever…..the dance continues…….

That is the better approach, for sure. Our dealer thanked me for not going off on them over the combined 51 days our truck spent there (as much as I was slowly dying on the inside), but A) the service department didn't design and build the truck so it's not their fault the lifters were made out of tin foil and B) in our case, they also had to wait on on a GM engineer to come to the dealer and give the final diagnosis and authorize the repair.

 

I had to get three Hertz rental cars and one dealership loaner in the first few months of ownership. The dealer initiated a P.O. for each rental car for me. I'm sure they didn't like having to pay for a rental car for weeks, but they did it anyway and I only had to put gas in them (I wasn't required to put gas in the dealer loaner). They absolutely should reimburse you, but it makes things more complicated since they didn't arrange the rental on your behalf (not that it's your fault at all).

 

I also totally agree that the service department staffing should take priority over sales. The service department gets way more foot traffic for both new and used vehicles wether they were purchased there or not and the experience there is what retains customers. I expect an awful sales experience, but It only happens once per car thankfully. I'm at the dealer several times a year for service (especially with this truck....) so I really only care about the quality of the service department.

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