Jump to content

Pros and Cons of Installing Later Transmission Thermostat with Lower Opening Temperature

Another JR

By Another JR
in 6.6L Gas V8 (L8T)

 Share

Recommended Posts

64BAwagon Senior Enthusiast

64BAwagon

Posted
Posted (edited)

I use tow haul whenever I have a trailer on, especially this 12k fifth wheel. 

I am assuming its 6th gear but its impossible to know since there isnt any indicator on the dash as to what gear its in. I wasnt aware that 6th got locked out in Tow/haul. I was assuming it was because the RPM's drop to 1500 at 64 Mph. 

 

There isnt any mention of the lock out in the HD manual. The only mention of it i  can see anywhere is on 1500's

 

Just for the sake of argument I have towed several different trailers with my trucks over the years, two of them were over 10k and I have probably logged well over 30k miles towing them. I am quite familiar with towing. 

Resized_20210311_160623_6590.jpeg

Edited by 64BAwagon
  • Replies 80
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

newdude
newdude

No cons, especially on an HD.  You will see a reduction in temps empty driving all day long.  Can it still build heat when towing?  Yes, but the fluid is flowing through the full cooling loop at a low

Grumpy Bear
Grumpy Bear

That is a flat out lie. Bolted the side of the transmission. Lord man, do it yourself. 

Another JR
Another JR

Yeah, that’s probably what I’ll do. I’m a bit concerned I’d have to add fluid, and the procedure for that may involve running the truck while adding fluid. (my BMW requires that). I’ll have to researc

Posted Images

Jettech1 Senior Enthusiast

Jettech1

Posted
Posted (edited)
1 hour ago, 64BAwagon said:

I use tow haul whenever I have a trailer on, especially this 12k fifth wheel. 

I am assuming its 6th gear but its impossible to know since there isnt any indicator on the dash as to what gear its in. I wasnt aware that 6th got locked out in Tow/haul. I was assuming it was because the RPM's drop to 1500 at 64 Mph. 

 

There isnt any mention of the lock out in the HD manual. The only mention of it i  can see anywhere is on 1500's

 

Just for the sake of argument I have towed several different trailers with my trucks over the years, two of them were over 10k and I have probably logged well over 30k miles towing them. I am quite familiar with towing. 

Just drop the shifter into manual and it will show what gear it's in bottom right of your speedometer screen.  Our camper is only 8klbs but yes, the tow/haul mode does lock out 6th gear.  And with tow/haul mode on your rpms at 64 should be around 2100 not 1500.  1500rpm is 6th gear.  And from the picture you posted I see you are a Grand Design owner too.  We have a 2023 Grand Design Imagine 2800BH.  LOVE IT!!!

Edited by Jettech1
  • Like 1
64BAwagon Senior Enthusiast

64BAwagon

Posted
Posted

Not sure where youre info comes from but on my truck T/H does not lock out 6th gear. I wish it would though. I dont want it in 6th because it just doesnt have the torque. The sweet spot seems to be a little over 2000 rpms which is where 5th puts me at 64. I do notice that above 66 mph or so it tries to shift into 6th even more. 

 

This 337RLS is our 2nd GD trailer, the first was a 2600RB that I pulled with a 1/2 ton double cab 5.3, It was definitely the top of the size I would tow with that truck 

Jettech1 Senior Enthusiast

Jettech1

Posted
Posted
22 minutes ago, 64BAwagon said:

Not sure where youre info comes from but on my truck T/H does not lock out 6th gear. I wish it would though. I dont want it in 6th because it just doesnt have the torque. The sweet spot seems to be a little over 2000 rpms which is where 5th puts me at 64. I do notice that above 66 mph or so it tries to shift into 6th even more. 

 

This 337RLS is our 2nd GD trailer, the first was a 2600RB that I pulled with a 1/2 ton double cab 5.3, It was definitely the top of the size I would tow with that truck 

Perhaps the 3500's don't do that.  My information comes from personal experience with my 2500.

Ray Pickle Enthusiast

Ray Pickle

Posted
Posted

I have a 20' 2500 and it does not lock out 6th gear. In tow/haul it rarely upshifts to 6th gear but it will under low load with speeds of 60 plus mph, "slight downhill", also agree that 5th is preferred cruising gear and the one that truck stays in on relatively level ground.

Jettech1 Senior Enthusiast

Jettech1

Posted
Posted
11 hours ago, Another JR said:

I can’t imagine they have different transmission programming for 2500 vs 3500. 

I looked everywhere today and couldn't find it.  I did read something about 6 months ago that said the 3500 gassers are not torque limited from take-off whereas the 2500's are.  I can't find it for the life of me but I do remember reading that somewhere.  I'll keep searching.

Another JR Senior Enthusiast

Another JR

Posted
  • Author
Posted
1 hour ago, Jettech1 said:

I looked everywhere today and couldn't find it.  I did read something about 6 months ago that said the 3500 gassers are not torque limited from take-off whereas the 2500's are.  I can't find it for the life of me but I do remember reading that somewhere.  I'll keep searching.

I think i remember reading that about the diesel. 

  • Like 1
Jettech1 Senior Enthusiast

Jettech1

Posted
Posted
8 hours ago, Another JR said:

I think i remember reading that about the diesel. 

You're probably right.  I did several months of intense research before I bought my truck at the end of August, so much that a lot of info got jumbled around.  I do know for a fact that my 2022 2500 gasser, in tow/haul mode locks out 6th gear.  The only other plausible explanation is that it was an update on the later build trucks.

  • Like 1
Pryme Senior Enthusiast

Pryme

Posted
Posted (edited)
3 hours ago, Jettech1 said:

You're probably right.  I did several months of intense research before I bought my truck at the end of August, so much that a lot of info got jumbled around.  I do know for a fact that my 2022 2500 gasser, in tow/haul mode locks out 6th gear.  The only other plausible explanation is that it was an update on the later build trucks.

Mine was built in July 22 same as yours I believe so I’ll have to try tow haul and see what happens.  

Edited by Pryme
Jettech1 Senior Enthusiast

Jettech1

Posted
Posted
9 hours ago, Pryme said:

Mine was built in July 22 same as yours I believe so I’ll have to try tow haul and see what happens.  

I tried it today unloaded on the highway.  Was going 65mph, rpms were at 1500.  Turned the TH mode knob, truck immediately downshifted into 5th gear, 2000rpms and stayed there.  It would not go into 6th gear.  It appears I made a bad assumption that the prior model years do that too.  To me that would suck while towing with the trans. constantly seeking out 6th gear in TH mode.  Too much shifting, and the only way to stop that would be to drop the shifter into manual mode and do it yourself.  And that would suck too because when the truck slows down up a long grade you would have to manually hit the switch to downshift into 4th gear, then manually make it go back into 5th.  That's too much BS in my opinion.  I'm hoping there's an update for those earlier model years.  That would drive me nuts when towing.  5th gear, 2000rpms is the sweet spot for towing and letting the trans. just do it's thing up and down grades and not going into 6th.

Another JR Senior Enthusiast

Another JR

Posted
  • Author
Posted
19 minutes ago, Jettech1 said:

I tried it today unloaded on the highway.  Was going 65mph, rpms were at 1500.  Turned the TH mode knob, truck immediately downshifted into 5th gear, 2000rpms and stayed there.  It would not go into 6th gear.  It appears I made a bad assumption that the prior model years do that too.  To me that would suck while towing with the trans. constantly seeking out 6th gear in TH mode.  Too much shifting, and the only way to stop that would be to drop the shifter into manual mode and do it yourself.  And that would suck too because when the truck slows down up a long grade you would have to manually hit the switch to downshift into 4th gear, then manually make it go back into 5th.  That's too much BS in my opinion.  I'm hoping there's an update for those earlier model years.  That would drive me nuts when towing.  5th gear, 2000rpms is the sweet spot for towing and letting the trans. just do it's thing up and down grades and not going into 6th.

That’s not how the transmission works in “L.”  The transmission shifts normally otherwise but will not upshift beyond the selected gear. For example, in L4, it will use 1, 2, 3, and 4, but won’t shift to 5 and 6. 

Jettech1 Senior Enthusiast

Jettech1

Posted
Posted
5 minutes ago, Another JR said:

That’s not how the transmission works in “L.”  The transmission shifts normally otherwise but will not upshift beyond the selected gear. For example, in L4, it will use 1, 2, 3, and 4, but won’t shift to 5 and 6. 

That's good to know.  So if it's in say 5th in L mode it will auto downshift into 4th if needed then go back to 5th on it's own?  If so that's a lot better than what I thought.  I was thinking you would have to pay total attention to what gear you're in when in L mode.  Great information, thank you!!

Another JR Senior Enthusiast

Another JR

Posted
  • Author
Posted
22 minutes ago, Jettech1 said:

That's good to know.  So if it's in say 5th in L mode it will auto downshift into 4th if needed then go back to 5th on it's own?  If so that's a lot better than what I thought.  I was thinking you would have to pay total attention to what gear you're in when in L mode.  Great information, thank you!!

Correct. It’s not a manual mode. It is a selectable top gear mode. The transmission will shift normally except it won’t upshift beyond your selection. It can be used in normal or tow/haul mode. 

  • Like 2
KARNUT Senior Enthusiast

KARNUT

Posted
Posted
7 hours ago, Another JR said:

Correct. It’s not a manual mode. It is a selectable top gear mode. The transmission will shift normally except it won’t upshift beyond your selection. It can be used in normal or tow/haul mode. 

Well it’s manual mode with the added feature. If you put it second gear and it hits the rev limit. It’s in manual mode.  

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • lanaderay
      5 Best Slide Down Gameplay Tips! 

      By lanaderay · Posted

      Are you playing Slide Down endlessly but your score is still low? Are you constantly crashing into obstacles as the game speed increases? Don't worry, this article will share 5 invaluable tips to help you master the race and impress your friends. Golden Rules 1. Look one step further. The mistake of 90% of new players is only staring at their character. The secret of experts is to look towards the top of the screen (where the slide is about to appear). This gives your brain an extra 0.5 - 1 second to process the situation and determine the direction of movement before the obstacle approaches. 2. Use gentle movements; don't swipe too hard. Slide Down is very sensitive. Moving your finger too forcefully or with excessive amplitude will cause your character to be thrown off course or crash into a wall. Practise moving your finger with small, decisive, and precise movements. 3. Don't be greedy for gold in dangerous locations. Gold coins are tempting for buying skins, but life is more important. If you see a gold coin right on the edge of a cliff or next to a spike trap, ignore it. Our goal is a High Score, and your score only increases if you survive. 4. Make the most of Power-ups. During the slide, you'll encounter items like Magnets (attract gold) or Shields (temporary invincibility). Never miss them! Especially the Shield, it's your "get out of jail free card" to help you get through those deadly fast sections. 5. Stay calm when speed peaks. When your score exceeds 500 or 1000, the game speed will be very fast. At this point, don't try to think logically; let your natural reflexes work. Take deep breaths and don't panic. Apply these 5 tips to your next game, and your leaderboard will surely improve dramatically. Good luck climbing the Slide Down leaderboard!
    • lingyuair
      Why I Recommend a Desiccant Air Dryer for Cleaner, Drier Compressed Air

      By lingyuair · Posted

      If you use compressed air regularly, one problem you cannot ignore is moisture. Water in the air line can cause rust, unstable air pressure, poor tool performance, and even damage to sensitive equipment. That is why I highly recommend using a desiccant air dryer. A desiccant air dryer is designed to remove moisture from compressed air by using drying materials such as activated alumina or molecular sieve. Compared with basic water separators, it can achieve much lower dew points, making it especially useful for applications that require dry and stable air. For workshops, painting systems, pneumatic tools, CNC machines, laser cutting equipment, and industrial production lines, a desiccant air dryer can make a big difference. It helps protect equipment, improve air quality, reduce maintenance costs, and extend the service life of the whole compressed air system. Another advantage is reliability. Many desiccant air dryers are built for continuous operation and can maintain stable drying performance even in demanding environments. For users who care about long-term efficiency and equipment protection, this is a smart investment. When choosing a desiccant air dryer, I suggest paying attention to air flow capacity, working pressure, dew point performance, regeneration method, and maintenance requirements. A good model should match your compressor system and actual air consumption. Overall, if moisture is causing problems in your compressed air system, a desiccant air dryer is definitely worth considering. It is practical, efficient, and highly useful for anyone who needs clean, dry, and reliable compressed air.
    • Jsdirt
      2027 GMC Sierra: Official Discussion

      By Jsdirt · Posted

      My brand new 2007 Silverado's wax frame was rust from end to end partway through it's SECOND winter here in MA. That stuff is completely useless.    
    • Jsdirt
      2027 GMC Sierra: Official Discussion

      By Jsdirt · Posted

      I went another direction after losing a trailer tire, thanks to not being able to access air at ANY of the 5 gas stations and garages I stopped at prior, with a Toyota Tacoma onboard, 50 miles from the Canadian border. They were either out of order, access was blocked, or the hose a few feet too short and I couldn't get any closer without risking damage to someone's property.   https://postimg.cc/gallery/X5QJ55w
    • Another JR
      Remote Start Noise 2024 2500 HD Gas

      By Another JR · Posted

      I took a 12 second video on my iphone but the file is too big to upload. I will have to figure out how to extract the audio or just do another start with an audio recording. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...