Chevy and GMC Duramax Diesel Forum banner

41 - 60 of 64 Posts

·
LHN...We ARE the Joneses
Joined
·
26,290 Posts
I don’t understand your reasoning to continue with crap when someone is just offering advice, that would be easier on the trans.
The 1st step to recovery is to realize your shortcomings. Congratulations.

:thumb
Pa Leeze
I've got more miles under my belt in more different Dmax platforms than you can begin to dream about.
Allison suggests when you tow engage towhaul and leave it engaged until your done towing, you’ve even said this, so what’s your problem.
Suggests, yes.
But the trans isn't going to fall out if you're underway with a load after a startup and realize the button hasn't been hit.
There ARE protections in place just for this. You don't need to pull over, stop, engage and start again.

I've described in detail what it does during this transition. In your frenzy of spewing vulgarities (how dare someone contradict me!), did you miss this?
'dunno;

In my line of work, there can be a lot of stop/start ups throughout the day.
Over hundreds of thousands of miles, I've occasionally missed the button, instantly realized this (difference in getting the load moving) and performed the engage under the exact conditions that you go off on like Chicken Little and the sky falling.

"just set the button and forget 'bout it"
Yes, I've said this ^^, mainly in response to newbies that are trying to use it as they would a 1/2-ton gasser, not wanting to engage it until absolutely needed. Or, engaging/disengaging while underway, thinking that they're saving fuel, as with a gasser.

Which is the wrong way with the Allison, as it wants to be in T/H all the time.
That's how it's designed, that's it's natural state of operation. Set it and leave it.

This was a Allison FAQ that I posted several years ago, some new breed youngster computer master for Allison decided to remove this FAQ,
It's called a Revision. Happens all the time in the Tech world, in every industry,....has for decades, still happens today and will every day in the future.

If it was an issue (as you want it to be), it would be there today....at the top of the list.
But it isn't, because....it isn't an issue.
 

·
Registered
Joined
·
85 Posts
Discussion Starter #43
Well we made it home, although not without an unfortunate situation. While descending the 6% grade I started smelling something like burnt rubber and heard an occasional squeal. As we were exiting off of I26 onto 74 I lost power steering and the brakes started getting real stiff. Thank God the exit had a large pull off. Stopped the rig, popped the hood and found my serpentine belt wrapped around my fan pulley. What would cause such a thing?? Serpentine belt was 6 months new. Well, started trying to turn pulleys and sure enough the lower idler was seized. 5 minutes to the irish parts store. New belt and pulley. The DW was an awesome assistant with keeping the tensioner held and we were back on the road in 40 minutes. Yes, I had tools with me of course.
 

Attachments

·
Registered
Joined
·
269 Posts
Not sure but you are most likely talking about 64. Comes out of Franklin nc towards hiawassee ga. It's about an 8% grade for the first few miles.

Sent from my SM-G960U using Tapatalk


I’m sure that must be it as I remember going through Franklin. Was pretty unnerving for sure. My front brakes were spewing smoke like crazy. Got so hot the left front end up locking up and wouldn’t release till they cooled off 15-30 minutes later.


Sent from my iPhone using Tapatalk Pro
 

·
Registered
Joined
·
280 Posts
Never heard of that lockout feature. Does it work on LBZ? I spent 6 weeks touring Utah. I did manual downshifts because I could judge how steep the downhill was, didn't want the computer to be guessing. yeah, adjust your electric brakes so you know they work. Occasionaly I've used them to stop the whole rig for an intersection just to be sure that they are working properly.

Touring Utah was the first time I heard the fan engage, its loud. And temp went up a bit past the halfway mark but far away from red area. Seems like the radiator serves to heat up the tranny fluid not vice versa.

It was a great trip and really makes you appreciate your dmax.

Do you have a load leveling hitch?
 

·
Registered
Joined
·
7,229 Posts
I've got more miles under my belt in more different Dmax platforms than you can begin to dream about.
Yep, and that's pretty much what your limited to on knowledge.

As usual your never man enough to admit your wrong about anything, you've been proven wrong several times.
One example of several the tires G614 and XPS RIB.

All I was doing was suggesting to not make this a habit and what I've been told by more experienced people with more knowledge.

But, I know you haven't f--k with me for several weeks so it was kinda expected, but over something so stupid, but that's hook.
I always pray that someday I will be able to put you on my ignore list.
Setting a pretty poor example for being a admin.

I'm happy to just let it be "Over on out"
I'll leave all the expert Allison questions for you, good or bad I don't care.
 

·
Registered
Joined
·
85 Posts
Discussion Starter #47
Never heard of that lockout feature. Does it work on LBZ? I spent 6 weeks touring Utah. I did manual downshifts because I could judge how steep the downhill was, didn't want the computer to be guessing. yeah, adjust your electric brakes so you know they work. Occasionaly I've used them to stop the whole rig for an intersection just to be sure that they are working properly.

Touring Utah was the first time I heard the fan engage, its loud. And temp went up a bit past the halfway mark but far away from red area. Seems like the radiator serves to heat up the tranny fluid not vice versa.

It was a great trip and really makes you appreciate your dmax.

Do you have a load leveling hitch?
Yes the lockout worked flawlessly. Wish ida knew about it on the way up. It was right there in my owners manual the whole time. And yes I have the load leveling hitch plus air bags.
 

·
Registered
Joined
·
280 Posts
this may not be your first time towing at a distance but in case it is, make sure that you can loosen the lug nuts on your trailer. You will be having blowouts no matter how good or new those tires are and I've had some problems with some outifts way over torquing those nuts. Even the roadside service guy couldn't get them off. So I keep a cheater pipe in the camper.
 

·
Registered
Joined
·
269 Posts
Several things:
1) You mentioned D and 3. How about simply locking out D, which gives you gears 1-4? To lock out D, simply press and hold the T/H button for several seconds until the slashed-D shows up on the display.
2) T/H will hold the gears longer on upshifts, and more aggressively downshift when braking. With the trailer, use T/H for sure.
3) You can use both T/H and locked-out D at the same time. It will still have the T/H characteristics, but it just won't go into 5th gear.

If going uphill, adjust your speed so the engine is 2200-2500 rpm. You may manually adjust the higher gear lockout (D=1-5, locked out D is 1-4, shifting to "3" is 1-3, etc.) as needed.

Since it's an LLY, watch your engine temps and know that if the dash gauge goes up one notch, you're at 220*F (most will show 210*F on the gauge at that point). You'll have to decide how hot you let it get. I'm a weenie so I don't like over 220*F, but then I have an aux radiator so it doesn't happen, and so far I still have the original headgaskets (but opinions vary).


So does a L5P have this same feature?


Sent from my iPhone using Tapatalk Pro
 

·
Registered
Joined
·
269 Posts
For a tractor that size you really ought to think about chains and binders instead of straps.


I plan to for sure. Just didn’t have them yet so used my four existing 3” wide webbing straps. They worked great but I did pull over after first 30min of trip to tighten them back down. Straps always tend to stretch a bit this need to be adjusted after the initial tie down.


Sent from my iPhone using Tapatalk Pro
 

·
Registered
Joined
·
378 Posts
Well we made it home, although not without an unfortunate situation. While descending the 6% grade I started smelling something like burnt rubber and heard an occasional squeal. As we were exiting off of I26 onto 74 I lost power steering and the brakes started getting real stiff. Thank God the exit had a large pull off. Stopped the rig, popped the hood and found my serpentine belt wrapped around my fan pulley. What would cause such a thing?? Serpentine belt was 6 months new. Well, started trying to turn pulleys and sure enough the lower idler was seized. 5 minutes to the irish parts store. New belt and pulley. The DW was an awesome assistant with keeping the tensioner held and we were back on the road in 40 minutes. Yes, I had tools with me of course.
How many miles on it? My first one went at about 110K.
 

·
Registered
Joined
·
40 Posts
I'm in NC too and have pulled across the mountains into TN and back. All you have to remember is Tow/Haul on, Gear Limiter set to L5, Diesel Brake On, Sit back and let it roll.
 

·
Registered
Joined
·
995 Posts
It continues to perplex me how folks can buy a new truck and then drive it like an old truck from 20 or 40 years ago. The new generation of GM trucks have Cruise Grade Braking Control as a feature and this feature is turned off when the driver puts the transmission in Range Select instead of leaving it in D or auto mode.

Cruise Grade Braking works incredibly well and I can set the cruise control for a chosen rate of speed for my going down a steep grade and the truck will shift to a lower gear automatically to keep the speed down and when it does this it also stops feeding gas or diesel to the engine to maximize engine braking. With a diesel engine, enabling the exhaust brake makes the engine braking even more effective. With a heavy load I have descended 4000 feet in less than 8 miles and the truck stayed at 35 mph the entire time which is what I needed for the twisty mountain road.

Tow/haul changes the shift points and keeps the torque converter clutch engaged longer and engages grade braking. The primary purpose is to minimize heat buildup in the transmission fluid. On the steepest grade in 105 degree temperatures at 8,0000 feet elevation with a very heavy load my truck's ATF never got above 230 degrees.

GM recommends using Tow Haul mode when the gross weight of the truck and its tow load exceed 75% of the vehicles GCWR. With my 2011 2500HD the GCWR is 24,500 lbs and so the Tow/Haul should be used when the combine load is greater than 18,375 lbs and my truck when empty weighs 6400 lbs so that would mean a trailer weight of more than 12,000 lbs to be using Tow/Haul mode. So for normal towing I do not use tow/haul mode unless I am using cruise grade braking on a long descent.

The one time I will use Range Select is to gain extra traction as starting in 2nd gear engages a mode for low traction situations and limits the power to the wheels when starting out. Helpful on soft shoulders and similar situations.
 

·
Registered
Joined
·
494 Posts
It continues to perplex me how folks can buy a new truck and then drive it like an old truck from 20 or 40 years ago. The new generation of GM trucks have Cruise Grade Braking Control as a feature and this feature is turned off when the driver puts the transmission in Range Select instead of leaving it in D or auto mode.

.
Even the group that does the Ike Gauntlet pulls on Fast Lane Truck have never learned how to properly use the grade braking and exhaust brake with the GM trucks. As a result they give the GM trucks a poor rating on the down hill runs.
 

·
Registered
Joined
·
40 Posts
I've not used the Cruise Grade Braking and I'm sure other's have more experience, I just don't need/want it to go into the extra overdrive gear, Transmission temp stays good and my mileage seems to be good. I'll have to give it a try and report back
 

·
Registered
Joined
·
85 Posts
Discussion Starter #58
It continues to perplex me how folks can buy a new truck and then drive it like an old truck from 20 or 40 years ago. The new generation of GM trucks have Cruise Grade Braking Control as a feature and this feature is turned off when the driver puts the transmission in Range Select instead of leaving it in D or auto mode.

Cruise Grade Braking works incredibly well and I can set the cruise control for a chosen rate of speed for my going down a steep grade and the truck will shift to a lower gear automatically to keep the speed down and when it does this it also stops feeding gas or diesel to the engine to maximize engine braking. With a diesel engine, enabling the exhaust brake makes the engine braking even more effective. With a heavy load I have descended 4000 feet in less than 8 miles and the truck stayed at 35 mph the entire time which is what I needed for the twisty mountain road.
I need to check in my owners manual to see if my LLY has this cruise braking control. I do know that I do not have exhaust brake.
 

·
Registered
Joined
·
7,229 Posts
Using towhaul when ever you tow anything any weight, and manual shifting never going above 5th gear, you shouldn’t ever see much above 210 - 215 trans temps.
Towing in 115*-120* outside temps up 7%-8% + grades, ECT and Tran temps around 210 - 215.
Believing what you read and actually experiencing both ways, before thinking that they know best, would be a much better choice before commenting on drivers from 20-40 years ago.
Most of us older farts know how to drive/tow without some dumb ass manual to read for the ones that don’t know, I guess you gots to start out somewhere, when you don’t know.

One thing that will never change is maintaining proper safe rpms while towing, it hasn’t since the late 60’s when I started towing, I don’t think this ever will change.

Having a EGT gauge pre-turbo helps with making better driving/towing decisions.

jwelder3,
Check out the DIY turbo brake option, 407driver has done this along with many others.
 

·
Registered
Joined
·
7,229 Posts
I see you have a 2019 Dmax. Can you explain the gear limiter set to L5?


Sent from my iPhone using Tapatalk Pro
Since no one has responded, I’m assuming your talking about limiting the gear to 5th.
Manual shift never go above 5th gear.
You should be able to select manual 5th while stopped or even driving.
Your trans will shift up to 5th gear normal while driving, and downshift normal slowing down even to a stop to 1st gear with the selector in M 5th gear.
 
41 - 60 of 64 Posts
Top