I don't fully agree with this guy,as the stock shift points are 5600 rpm,not the 6,000 he's using,but still a decent article on gearing

[Docwagon1776]

Maybe you are hung up on semantics... If someone presses the accelerator down another 5% and the truck fails to go any faster, what do you call that?

So first you said acceleration isn't linear. Now you're saying there is no acceleration?

If you are pushing down on the pedal 5% more and the rpm isn't increasing, your truck has an issue. Your specific truck.

If it's lugging, you'll know it without a scanner. It's not subtle. Automatics in these trucks aren't lugging, though, even in your super heavy classic 1/2 ton.

 

[04fxdwgi]

Maybe you are hung up on semantics... If someone presses the accelerator down another 5% and the truck fails to go any faster, what do you call that?

I call it a problem with your truck if your truck isn't downshifting properly, if needed, to not "lug".

The 8 speed with 3.21's and the 20" wheels works just fine for me when hauling my 7k lb boat around. I do use tow / haul mode when needed. Common sense rules here.

 

[ramffml]

Maybe you are hung up on semantics... If someone presses the accelerator down another 5% and the truck fails to go any faster, what do you call that?

You're trying to pretend there is an issue, when there isn't. There are combinations of load, grade, and speed that will require the truck to downshift from 8th to 7th:
A) That doesn't mean it was lugging in 8th. You can find similar combinations when the truck is in 5th and requires a downshift to 4th, doesn't mean it was lugging in 5th.
B) Downshifting is a feature, that's the entire point of a transmission especially one with high gear counts like an 8 or 10 speed.
C) The software tuning is really great on these trucks, especially the 2 overdrives are extremely well tuned and linear, if you have music on or whatever and you're not trying to find the downshifts/upshifts, you won't notice them.

You're the only one complaining about lugging and doing silly by neutering your transmission. Perhaps it's not the rest of the world that's wrong?

Only reason I'm arguing with you is because you're trying to state your preference as a fact. If you just said "I like that is is more responsive in 7th", which it factually would be, I wouldn't have said a thing, you do you. But trying to claim the truck can't do it and/or it's poorly tuned (lugging), well you're definitely wrong.

So yes, you call it "semantics", but words have meanings and implications. "lugging" implies there is a problem, when really you just have a different preference (which puts the emphasis on you, not the fault of the truck).

 

[Bmags]

I call it a problem with your truck if your truck isn't downshifting properly, if needed, to not "lug".

The 8 speed with 3.21's and the 20" wheels works just fine for me when hauling my 7k lb boat around. I do use tow / haul mode when needed. Common sense rules here.

Geez 5% people... 5%. It's not going to downshift and drop a gear with a *slight* increase in throttle. Sure, you use tow/haul mode which will keep it out of 8th gear in the lower (luggy) RPM range when towing. Thanks for proving my point

 

[Bmags]

You're trying to pretend there is an issue, when there isn't. There are combinations of load, grade, and speed that will require the truck to downshift from 8th to 7th:
A) That doesn't mean it was lugging in 8th. You can find similar combinations when the truck is in 5th and requires a downshift to 4th, doesn't mean it was lugging in 5th.
B) Downshifting is a feature, that's the entire point of a transmission especially one with high gear counts like an 8 or 10 speed.
C) The software tuning is really great on these trucks, especially the 2 overdrives are extremely well tuned and linear, if you have music on or whatever and you're not trying to find the downshifts/upshifts, you won't notice them.

You're the only one complaining about lugging and doing silly by neutering your transmission. Perhaps it's not the rest of the world that's wrong?

Only reason I'm arguing with you is because you're trying to state your preference as a fact. If you just said "I like that is is more responsive in 7th", which it factually would be, I wouldn't have said a thing, you do you. But trying to claim the truck can't do it and/or it's poorly tuned (lugging), well you're definitely wrong.

So yes, you call it "semantics", but words have meanings and implications. "lugging" implies there is a problem, when really you just have a different preference (which puts the emphasis on you, not the fault of the truck).

Please re-read my post... I'm not talking about downshifting. For a slight increase in throttle, if the truck fails to increase in speed, that means it doesn't have enough power in that RPM range to overcome the forces against it (ie wind, load, etc). Sure, mash the pedal down 15-20%, hear it downshift... and act confused about my post. Whatever dude.

The rest of the world with a 3.92 truck factory does not have these issues, you are right. Heck there are lots of folks out there that still love MDS too and don't notice when it kicks in. If you are unwilling to perform my test and see the factual results for yourself well I guess we are at an impasse then. The numbers don't lie.

I also just re-calibrated my butt this morning.

 

[Sillygoose]

bad guys should be forced to read this thread every day.

 

[ramffml]

Please re-read my post... I'm not talking about downshifting.

Yes, we absolutely are. You press the pedal, but the engine won't make the required power so it downshifts to get the power it needs. This is exactly how it works in every car/truck/transmission combo.

It doesn't mean the engine is lugging, it just means at certain point the engine needs to downshift to make power.

Essentially what you are asking for, is a sportier tune. That doesn't mean the truck is lugging, it just means you want it to downshift quicker, hold rpms longer/higher etc.

 

[Bmags]

Yes, we absolutely are. You press the pedal, but the engine won't make the required power so it downshifts to get the power it needs. This is exactly how it works in every car/truck/transmission combo.

It doesn't mean the engine is lugging, it just means at certain point the engine needs to downshift to make power.

Essentially what you are asking for, is a sportier tune. That doesn't mean the truck is lugging, it just means you want it to downshift quicker, hold rpms longer/higher etc.

Correct, the issue is that the engine does not make the required power, however the scenario I'm talking about is BEFORE the downshift limit is reached. That gray zone called lugging (which is abundant in the 3.21 setup). Have you hooked up a logger tool yet, or still flying by the seat of your pants with what you know to be true?

 

[Wild one]

I think if it was me,i'd of bought a set of Brandon's paddles , and upped the shift points to 6,000/6100 and left 8th gear active. The paddles are fun to play with and make it easy to lock out 8th when you don't want it.
I've had paddles in my truck for 10 years,and they're one of the best interior options i've ever done.

 

[ramffml]

Correct, the issue is that the engine does not make the required power, however the scenario I'm talking about is BEFORE the downshift limit is reached. That gray zone called lugging (which is abundant in the 3.21 setup). Have you hooked up a logger tool yet, or still flying by the seat of your pants with what you know to be true?

You don't understand what lugging is. That's the problem in a nutshell. Just because the engine needs to downshift to make more power, doesn't mean it was lugging before that point.

 

[Bmags]

I think if it was me,i'd of bought a set of Brandon's paddles , and upped the shift points to 6,000/6100 and left 8th gear active. The paddles are fun to play with and make it easy to lock out 8th when you don't want it.
I've had paddles in my truck for 10 years,and they're one of the best interior options i've ever done.

Ya know... you're alright

 

[CanuckRam1313]

Okay... maybe out of place here, or in place... nonetheless... I toss it out just because I'm on this page now and reading from this point....

One's 8spd transmission temps and more so (IMPO) when it was last serviced / current mileage and/or current condition of ones fluid & filter "could" also play a determining factor in how ones transmission shifts/acts/reacts to throttle input/shifting characteristics, etc.

We know definitively that our 8spds must get serviced, and more regular servicing has proven to be a known benefit long term/overall vs just running on the original factory fluid indefinitely.

Apologies if this was covered in previous posts on this particular thread, but from my experience with the 33+ years of driving and well into the several million+ km's I've driven to date... I know that any vehicle I've owned (about 24/25 to date & auto or manual) that having good fluid and filtration contributed greatly to the overall performance / shifting characteristics of my transmissions.

If I'm talking out of my butt... apologies and let me have it... I can take it

 

[Docwagon1776]

Correct, the issue is that the engine does not make the required power, however the scenario I'm talking about is BEFORE the downshift limit is reached. That gray zone called lugging (which is abundant in the 3.21 setup). Have you hooked up a logger tool yet, or still flying by the seat of your pants with what you know to be true?

It's not lugging, as has been explained to you. You just have an expectation that's not in line with reality. If you think acceleration will be linear, than even electric motors "lug". A vehicle that can't accelerate from 80-120 as fast as it accelerated from 10-50 is "lugging".

Force required to accelerate is parabolic, not linear, even if we were operating with no internal loss. Add in real world forces of wind resistance, internal drivetrain loss, friction, etc. and it's obviously not going to be linear even if it's a single speed vehicle.

In short, you're confusing one slope of a parabolic application of force to a different, less aggressive, slope as "lugging".

If these trucks actually lugged like you keep saying, where are all the posts about broken parts? Lugging is like hammering on the pistons, transmitting force into them against the direction they are traveling. That would shorten the lifespan of the rotating assembly. We get a bajillion posts about bad cams and lifters, so if people were blowing piston rings or breaking connecting rods, we'd know it. You would see the 3.21 equipped trucks having a statistically significant difference in the lifespan of the weakest links in the rotating assembly due to the hammering they would take over the 3.91. But, we don't. So...logically what's that tell you?

 

[Bmags]

It's not lugging, as has been explained to you. You just have an expectation that's not in line with reality. If you think acceleration will be linear, than even electric motors "lug". A vehicle that can't accelerate from 80-120 as fast as it accelerated from 10-50 is "lugging".

Force required to accelerate is parabolic, not linear, even if we were operating with no internal loss. Add in real world forces of wind resistance, internal drivetrain loss, friction, etc. and it's obviously not going to be linear even if it's a single speed vehicle.

In short, you're confusing one slope of a parabolic application of force to a different, less aggressive, slope as "lugging".

If these trucks actually lugged like you keep saying, where are all the posts about broken parts? Lugging is like hammering on the pistons, transmitting force into them against the direction they are traveling. That would shorten the lifespan of the rotating assembly. We get a bajillion posts about bad cams and lifters, so if people were blowing piston rings or breaking connecting rods, we'd know it. You would see the 3.21 equipped trucks having a statistically significant difference in the lifespan of the weakest links in the rotating assembly due to the hammering they would take over the 3.91. But, we don't. So...logically what's that tell you?

Ok, let's try this again for the cool kids in the back of the class that haven't been paying attention... Don't make me get out the ruler!

I'm not talking about linear acceleration, I'm talking about a proportional change in speed with respect to increased throttle. Fellas, I don't see why you are trying to convince me I'm wrong here. I have the data from my truck, and the numbers show that the engine does not produce a corresponding increase in speed for increased throttle under load in 8th gear.

The reason our trucks do not have issues is that folks will continue to press the pedal down further until they get a response from the truck (until it shifts into 7th gear for instance) and then accelerates as expected. This is fine... and a completely understandable way for an engine/tranny setup to work. HOWEVER, IT DOES NOT NEGATE THE FACT THAT THERE IS NO POWER AVAILABLE IN 8TH GEAR. Hence, the engine lugs in 8th gear... well unless you are going 90+ as Wild One states... where the engine is producing enough power.

 

[Sillygoose]

your harris bumper sticker is what's lugging that 8th gear

 

[Ken226]

This thread

 

[Docwagon1776]

Ok, let's try this again for the cool kids in the back of the class that haven't been paying attention... Don't make me get out the ruler!

I'm not talking about linear acceleration, I'm talking about a proportional change in speed with respect to increased throttle. Fellas, I don't see why you are trying to convince me I'm wrong here. I have the data from my truck, and the numbers show that the engine does not produce a corresponding increase in speed for increased throttle under load in 8th gear.

The reason our trucks do not have issues is that folks will continue to press the pedal down further until they get a response from the truck (until it shifts into 7th gear for instance) and then accelerates as expected. This is fine... and a completely understandable way for an engine/tranny setup to work. HOWEVER, IT DOES NOT NEGATE THE FACT THAT THERE IS NO POWER AVAILABLE IN 8TH GEAR. Hence, the engine lugs in 8th gear... well unless you are going 90+ as Wild One states... where the engine is producing enough power.

I paid enough attention to notice you edited your post to go from linear to proportional, then claimed no acceleration, and ignored the question as to which it actually is.

Nobody, literally nobody, is arguing the truck may not have enough power in 8th gear to accelerate some hypothetical load in some hypothetical condition at all. Literally nobody is claiming it may always be able to stay in 8th gear to even maintain speed.

But...what everybody but you in the thread understands is what "lugging" means.

 

[ramffml]

Fellas, I don't see why you are trying to convince me I'm wrong here.

Because you're wrong?

HOWEVER, IT DOES NOT NEGATE THE FACT THAT THERE IS NO POWER AVAILABLE IN 8TH GEAR.

I've towed small trailers on the freeway up grades/bridges at 110+ kph and 0 down shifting. Lots of power. I've travelled solo on a freeway up the canadian shield for 3 hours straight and had to downshift twice. The horror. (I travel this exact route frequently so yes I can predict exactly when/where it needs to downshift, it's literally 2 or 3 times including numerous changes in grade)

Hence, the engine lugs in 8th gear...

We've explained this. Having to downshift has nothing to do with lugging per se. Lugging implies a defect in the hardware or tuning, but every transmission/engine combination out there will have to downshift to make more power when it needs to.

In otherwords, you're emphatically claiming the 3.21 has issues, when in fact you're using incorrect terminology to describe your preference for a sportier tune.

 

[Bmags]

Reading your post it's clear you still can't comprehend what I am saying. That's ok, maybe if you keep talking about downshifting and a sport tune you'll get me to change what the data shows.

I don't want the truck to downshift sooner... I'm stating the fact that the truck from the factory has shift points that do not meet the power needs for the truck being used like a truck. It inherently lugs in 8th gear, most likely to keep the EPA happy. It's a fact, no need to argue... the truck upshifts earlier than it should so it operated in the most fuel efficient mode to get the best window sticker MPG (controlled environment, flat road, etc etc).

In the meantime I'd like to hear more about those paddles.

 

[ramffml]

Reading your post it's clear you still can't comprehend what I am saying. That's ok, maybe if you keep talking about downshifting and a sport tune you'll get me to change what the data shows.

Yes dear. Everybody else here in this thread is wrong, you're right.

In the meantime I'd like to hear more about those paddles.

Sounds frisky....!